I believe, O Lord, and I confess that You are truly the Christ, the Son of the living God, who came into the world to save sinners, of whom I am chief.
War (not war crimes) and justice is different. Vigilantism is not the same thing, and most of the time is morally wrong. Unless you're actually saving someone's life, taking another's life because of some political ideology is morally bankrupt and you should be in jail.
You don't see how fighting fascism is fighting to save lives?
What, do you only see the lives of groups that nazis won't exterminate as lives for the purpose of "saving lives"? Do you understand what happens if fascists gain power again?
The most enlightened possible take is "murder is bad no matter what" while mass murderers continue murdering and don't give a fuck about how you feel about murder and won't bother waiting around for some absent authority to arrest them.