I agree about the other characters being scumbags too, it's just Michael initially really looks like the only "good guy" in the family and then not only becomes a killer (not just once, when he killed Sollozzo and the corrupt cop) but a mafioso by "profession", without ANY internal struggle to be shown, he switches "morality" extremely quickly, quicker even than a chameleon changes color. The other characters at least were "bad" from the beginning, except Vito's scenes as a child, but once grown up, we have seen what happened.

But about Vito, in the movie they left out details from the book than make him worse than Michael even: in the book, there is an explanation why Luca Brasi is so loyal to him; Vito bailed him out and probably paid bribes to drop the case, when Brasi was arrested for burning his own newborn child alive. Vito obviously had no problem with that; on the contrary, he was fine with using child murder as assurance for the "murder machine"'s loyalty.

Tom Hagen, too: when he almost witnessed the act of pedophilia by Jack Woltz (again, this was dropped from the movie), he didn't report to Vito and Vito didn't order to cut Woltz's [censored] off. As long as the pedophile did what they said, they didn't care about the rest.

Michael pissed me more in the movies, where these scenes were dropped, and I hadn't read the book when I watched the 1st movie the 1st time, and the other characters were already represented as scumbags from the beginning (still have no idea why people say they are idealized, I don't think that gaining sympathy for them was the film creator's intention, just look at the final scene where Michael "repents his sins" in the church in a newborn baby's presence and right at the same moment his "soldiers" blast away everybody).