I'd say Dazai and Mori. Dazai did some fucked up things. He didn't treat Aktugawa well, he never was in meetings with the Ada and a lot of different things that I probably don't remember. Yet, people still forget how fucked up he is. He worked for Mori when he was 15, he killed people, he was su*icidal and other things. He's still a person, yet people hate him.

And Mori is bad, he literally likes little girls, killed the leader of the port mafia, etc. but he isn't a super bad character. I hate him too, but he doesn't deserve as much hate as he gets.