We must first of all know that when Islam came, it came among 365 Arab Pagan Tribes, and they were all idol worshipers, women abusers and enslavers. Islam came and fought idol worshiping, oppressing women and racism and slavery (which is by the way clearly promoted in the Bible's Old and New Testaments) in many bloody battles that were imposed upon the Muslims without any choice for the Muslims. So, if we hear about few pigs from the Pagans getting killed for the sake of Allah Almighty, it should not raise any red flags in our minds about the validity of Islam and it's tolerance to non-Muslims.
Narrated 'Aisha: "Whenever Allah's Apostle was given the choice of one of two matters, he would choose the easier of the two, as long as it was not sinful to do so, but if it was sinful to do so, he would not approach it.Allah's Apostle never took revenge (over anybody) for his own sake but (he did) only when Allah's Legal Bindings were outraged in which case he would take revenge for Allah's Sake. (Translation of Sahih Bukhari, Virtues and Merits of the Prophet (peace be upon him) and his Companions, Volume 4, Book 56, Number 760)"
Narrated 'Aisha: "Whenever Allah's Apostle was given the choice of one of two matters he would choose the easier of the two as long as it was not sinful to do so, but if it was sinful, he would not approach it. Allah's Apostle never took revenge over anybody for his own sake but (he did) only when Allah's legal bindings were outraged, in which case he would take revenge for Allah's sake. (Translation of Sahih Bukhari, Good Manners and Form (Al-Adab), Volume 8, Book 73, Number 147)"
Narrated Aisha: "Whenever the Prophet was given an option between two things, he used to select the easier of the tow as long as it was not sinful; but if it was sinful, he would remain far from it. By Allah, he never took revenge for himself concerning any matter that was presented to him, but when Allah's Limits were transgressed, he would take revenge for Allah's Sake. (Translation of Sahih Bukhari, Limits and Punishments set by Allah (Hudood), Volume 8, Book 81, Number 777)"
Narrated Jabir bin ‘Abdullah: That he fought in a Ghazwa towards Najd along with Allah's Apostle and when Allah's Apostle returned, he too, returned along with him. The time of the afternoon nap overtook them when they were in a valley full of thorny trees. Allah's Apostle dismounted and the people dispersed amongst the thorny trees, seeking the shade of the trees. Allah's Apostle took shelter under a Samura tree and hung his sword on it. We slept for a while when Allah's Apostle suddenly called us, and we went to him, to find a bedouin sitting with him. Allah's Apostle said, "This (bedouin) took my sword out of its sheath while I was asleep. When I woke up, the naked sword was in his hand and he said to me, 'Who can save you from me?, I replied, 'Allah.' Now here he is sitting." Allah's Apostle did not punish him (for that) .(Translation of Sahih Bukhari, Military Expeditions Led By The Prophet (pbuh) (Al-Maghaazi), Volume 5, Book 59, Number 458)"
Narrated Jafar bin 'Amr bin Umaiya: I went out with 'Ubaidullah bin 'Adi Al-Khaiyar. When we reached Hims (i.e. a town in Syria), 'Ubaidullah bin 'Adi said (to me), "Would you like to see Wahshi so that we may ask him about the killing of Hamza?" I replied, "Yes." Wahshi used to live in Hims. We enquired about him and somebody said to us, "He is that in the shade of his palace, as if he were a full water skin." So we went up to him, and when we were at a short distance from him, we greeted him and he greeted us in return. 'Ubaidullah was wearing his turban and Wahshi could not see except his eyes and feet. 'Ubaidullah said, "O Wahshi! Do you know me?" Wahshi looked at him and then said, "No, by Allah! But I know that 'Adi bin Al-Khiyar married a woman called Um Qital, the daughter of Abu Al-Is, and she delivered a boy for him at Mecca, and I looked for a wet nurse for that child. (Once) I carried that child along with his mother and then I handed him over to her, and your feet resemble that child's feet." Then 'Ubaidullah uncovered his face and said (to Wahshi), "Will you tell us (the story of) the killing of Hamza?" Wahshi replied "Yes, Hamza killed Tuaima bin 'Adi bin Al-Khaiyar at Badr (battle) so my master, Jubair bin Mut'im said to me, 'If you kill Hamza in revenge for my uncle, then you will be set free." When the people set out (for the battle of Uhud) in the year of 'Ainain ..'Ainain is a mountain near the mountain of Uhud, and between it and Uhud there is a valley.. I went out with the people for the battle. When the army aligned for the fight, Siba' came out and said, 'Is there any (Muslim) to accept my challenge to a duel?' Hamza bin 'Abdul Muttalib came out and said, 'O Siba'. O Ibn Um Anmar, the one who circumcises other ladies! Do you challenge Allah and His Apostle?' Then Hamza attacked and killed him, causing him to be non-extant like the bygone yesterday. I hid myself under a rock, and when he (i.e. Hamza) came near me, I threw my spear at him, driving it into his umbilicus so that it came out through his buttocks, causing him to die. When all the people returned to Mecca, I too returned with them. I stayed in (Mecca) till Islam spread in it (i.e. Mecca). Then I left for Taif, and when the people (of Taif) sent their messengers to Allah's Apostle, I was told that the Prophet did not harm the messengers; So I too went out with them till I reached Allah's Apostle. When he saw me, he said, 'Are you Wahshi?' I said, 'Yes.' He said, 'Was it you who killed Hamza?' I replied, 'What happened is what you have been told of.' He said, 'Can you hide your face from me?' So I went out when Allah's Apostle died, and Musailamah Al-Kadhdhab appeared (claiming to be a prophet). I said, 'I will go out to Musailamah so that I may kill him, and make amends for killing Hamza. So I went out with the people (to fight Musailamah and his followers) and then famous events took place concerning that battle. Suddenly I saw a man (i.e. Musailamah) standing near a gap in a wall. He looked like an ash-colored camel and his hair was dishevelled. So I threw my spear at him, driving it into his chest in between his breasts till it passed out through his shoulders, and then an Ansari man attacked him and struck him on the head with a sword. 'Abdullah bin 'Umar said, 'A slave girl on the roof of a house said: Alas! The chief of the believers (i.e. Musailamah) has been killed by a black slave."(Translation of Sahih Bukhari, Military Expeditions Led By The Prophet (pbuh) (Al-Maghaazi), Volume 5, Book 59, Number 399)"
Here we clearly see that the Prophet did not have Wahshi killed for killing the Prophets beloved uncle.
Personal Revenge Helps the Devil:
Narrated Sa'id ibn al-Musayyab: "While the Apostle of Allah (peace_be_upon_him) was sitting with some of his companions, a man reviled AbuBakr and insulted him. But AbuBakr remained silent. He insulted him twice, but AbuBakr controlled himself. He insulted him thrice and AbuBakr took revenge on him. Then the Apostle of Allah (peace_be_upon_him) got up when AbuBakr took revenge.
AbuBakr said: Were you angry with me, Apostle of Allah?
The Apostle of Allah (peace_be_upon_him) replied: An angel came down from Heaven and he was rejecting what he had said to you. When you took revenge, a devil came down. I was not going to sit when the devil came down. (Translation of Sunan Abu-Dawud, General Behavior (Kitab Al-Adab), Book 41, Number 4878)"
In the above narrations about our Prophet peace be upon him, we clearly without any doubt that he never seeked any personal revenge for his own sake. Prophet Muhammad was Allah Almighty's Messenger, and the leader of the Muslims. He never took things personal. He always seeked the higher level and bigger picture of things. If he executed some pigs, then it is crystal clear from the above narrations about him that he didn't do it for his own personal sake or revenge, but the sake of Allah Almighty, Islam and the Muslims.
2- Allah Almighty revenged for our Prophet and Islam:
In the following narration, we see a list of names of some Pagans whom the hypocrites of the Christian "Answering Islam" team seem to love and adore very much that they made such a big deal out of them, and decided to invent fabricated cheap lies against our beloved Prophet. In the following narration, we see how Allah Almighty revenged for our beloved Prophet and killed some of the pigs who caused a lot of sufferings for the Muslims 1400 years ago, whom the Christian "Answering Islam" hypocrites love and adore so much, that insha'Allah (may Allah Almighty Will it) will end up with them in Hell Fire!
This narration doesn't in anyway prove the false lies that our Prophet is full of hatred that he wished the death and torture of non-Muslims. This lie's statement is too general and too vast. It's easy for some hater of Islam to say such a statement. But as we've seen in the above narrations, our beloved Prophet peace be upon him is full of forgiveness and love toward others.
3- Repelling evil with good in Islam:
Allah Almighty in the Noble Quran commands us to return the evil that is done to us by others to not only with good, but with best!.
Let us look at Noble Verse 13:22 "Those who patiently persevere, seeking the countenance of their Lord; establish regular prayers; spend out of (the gifts) We have bestowed for their sustenance, secretly and openly; and turn off evil with good: for such there is the final attainment of the (Eternal) Home."
Let us look at Noble Verse 23:96 "Repel evil with that which is best: We are Well-acquainted with the things they say."
Let us look at Noble Verse 41:34 "Nor can goodness and evil be equal. Repel (evil) with that is better: Then will he between whom and thee was hatred become as it were thy friend and intimate!."
Let us look at Noble Verse 28:54 "Twice will they be given their reward, for that they have persevered, that they avert evil with good, and that they spend (in charity) out of what We have given them."
Let us look at Noble Verse 42:40 "The recompense for an injury is an injury equal thereto (in degree): but if a person forgives and makes reconciliation, his reward is due from Allah: for (Allah) Loveth not those who do wrong."
Allah Almighty loves those who restrain anger: "Those who spend (freely), whether in prosperity, or in adversity; who restrain anger, and pardon (all) men; for Allah loves those who do good. (The Noble Quran, 3:134)"
Whether people speak evil of you, in your presence or behind your back, or they do evil to you in either of those ways, all is known to Allah Almighty. It is not for you to punish. Your best course is not to do evil in your turn, but to do what will best repel the evil. Two evils do not make a good.
You do not return good for evil, for there is no equality or comparison between the two. You repel or destroy evil with something which is far better, just as an antidote is better than poison. You foil hatred with love. You repel ignorance with knowledge, folly and wickedness with the friendly message of Revelation. The man who was in bondage of sin, you not only liberate from sin, but make him your greatest friend and helper in the cause of Allah Almighty!. Such is the alchemy of the Word of Allah Almighty!. Your credit for returning evil with good and paying for charity is double. Also if you forgive and return the evil with good, then Allah Almighty will love you and reward you.
4- No fighting is allowed in Mecca:
Narrated Abu Huraira: "In the year of the Conquest of Mecca, the tribe of Khuza'a killed a man from the tribe of Bani Laith in revenge for a killed person, belonging to them. They informed the Prophet about it. So he rode his Rahila (she-camel for riding) and addressed the people saying, "Allah held back the killing from Mecca. (The sub-narrator is in doubt whether the Prophet said "elephant or killing," as the Arabic words standing for these words have great similarity in shape), but He (Allah) let His Apostle and the believers over power the infidels of Mecca. Beware! (Mecca is a sanctuary) Verily! Fighting in Mecca was not permitted for anyone before me nor will it be permitted for anyone after me. It (war) in it was made legal for me for few hours or so on that day. No doubt it is at this moment a sanctuary, it is not allowed to uproot its thorny shrubs or to uproot its trees or to pick up its Luqatt (fallen things) except by a person who will look for its owner (announce it publicly). And if somebody is killed, then his closest relative has the right to choose one of the two-- the blood money (Diyya) or retaliation having the killer killed. In the meantime a man from Yemen came and said, "O Allah's Apostle! Get that written for me." The Prophet ordered his companions to write that for him. Then a man from Quraish said, "Except Al-Iqhkhir (a type of grass that has good smell) O Allah's Apostle, as we use it in our houses and graves." The Prophet said, "Except Al-Idhkhiri.e. Al-Idhkhir is allowed to be plucked." (Translation of Sahih Bukhari, Knowledge, Volume 1, Book 3, Number 112)"