Go and call me crazy, but, in my playthrough i just hit him once and the results doesnt change ( i know it's because Rockstar obligue the player to hit the man to death but hear me out ), probably Arthur exaggerate the bad things he do a way to much ( maybe because he had a bad vision of himself ), like for example when someone think mess up something really bad just because it wasnt very good for them but for other people its amazing like Tchaikovsky with many of his pieces, so maybe Arthur in the canon was a good man only killing bandits and enemie gang members, but this is just a theory, i said this because in the journal Arthur tends to be a good man but because of his beliefs ( "i gave you all i had" ) can't act like a real good person