Goodfellas was not impartial. Henry Hill and others in Jimmy Burke's crew were much worse than what the movie let on. Scorsese and Nick Pileggi had to have known it, especially Pileggi, who'd been an investigative journalist covering the mob for years. Scorsese knew they were worse based on his own experiences growing up. Scorsese and Pileggi whitewashed the Burke crew, and they knew it. They took an otherwise dark, disturbing story and made it intriguing and acceptable to mainstream American audiences.
I saw Jimmy kill a bunch of his friends instead of giving them the money he owed. I saw Liotta's character cheat on his wife, get addicted to coke, and rat on all his friends. I saw Pesci's character kill two guys simply because they mouthed off at him. They changed some stuff to make them more appealing initially but that's far from white-washing. Paulie was the only one they changed to make look a lot better than he was, but he was the 5th most important character in the movie.
