In regards to separating art from the artist, if you listen to a burzum song, what the fuck do you expect him to be like if not fucked in the head? To me, if however the artist is as a person lines up with his art, he becomes a character and it's fine. Sex pistols f.ex., I don't want to stab my girlfriend and od on heroin, in fact I stand against it, but that's kind of the fucked up vibe I'm looking for when listening to that music.
Opposite example is like Louis CK, who I viewed as some sort of a voice of reason. Then turns out he's actually some weirdo creep and that completely put me off on his stand up, even though what he did wasn't even that bad