Arthur wasn’t an angel but at least he had some lines he wouldn’t cross he wouldn’t kill innocent people unlike the rest of them Dutch basically turned into a madman who lied to everyone who ever cared about him Ross and Milton were people who did things just as bad if not worse then the gangs they hunted down Colm killed indiscriminately and didn’t care about his own gang only strength in numbers instead of making a loyal gang and Colonel Favours lied stolen and basically ran the Wapiti trip out of the state

I only included Arthur because he was evil until chapter 6. After the bank heist, he threatened to kill a kid just because he disliked Arthur for killing his father. I doubt Arthur was going to kill him, but anyway. "Well, maybe when your mother's finished mourning your father, I'll keep her in black. On your behalf, you think on that BOAH." This is what Arthur said when he threatened him.

And yet in chapter 6 he helped that same Boy and his mother to get on to a better life that’s was the whole point of Arthur’s story you see him turn from a cold blooded gunslinger into someone who wants to right the wrongs he himself cause

Was going to say Dutch but he really does have some tough competition. Allende, Ross and Fussar are my rival top 3 with Dutch for most evil, primarily because those three appear to be evil for evil's sake - they don't have any other underlying reasons for their behaviour.

Bill and his gang do some terrible things in RDR 1 but Bill is dumb and mad, Colm likewise, plus Dutch is a genuine threat to some extent so he has an underlying reason to hate him anyway, Favours also did terrible things but it was motivated mainly by insecurity and a desire to prove himself, Milton was trying to do some good in eliminating an outlaw gang, was just doing his job, and also retained a small shred of integrity by never breaking the law, so again, he isn't quite as bad as some others. Arthur was never really evil at all imo.

Well even arthur is good person and not evil

Its considered player's choices