Is it really just based on the winner of a conflict to you, personally? Like if there was an American war hero that personally tortured and brutally killed or desecrated all the Nazis he could along with butchering civilians under the justification "Germans aren't humans", would you see that man as a war criminal even if you're an American and he is listed in many major victories?
Like to the country, someone that does evil things for its sake can be seen as a hero, so from their POV they aren't "evil" or war criminals.