Gangs of New York (2002) - 1 question

Question: Can someone please explain to me why the audience and Amsterdam are supposed to hate Butcher so much and think he's a loathesome person? He killed Vallon during a fight, fair and square, and was nothing but respectful to his dead enemy. He almost seemed to have regretted killing Vallon. He didn't act like a worse scum than anyone else until quite a while into the film.

Answer: Well, rather obviously, Amsterdam hates him because he killed his father. I mean, wouldn't you? It hardly matters that the fight was fair and that Bill showed respect about it, Amsterdam's not exactly likely to turn round, say "oh, that's alright then" and walk away. William Cutting (or William Poole, as he was in reality) was a ruthless, vicious man, who pretty much stopped at nothing to cement his control of the area. Whether he was actually worse than many of the others is questionable, but the film is based on Amsterdam's view of things - in that view, Bill is the enemy and we're supposed to see him as such.