To me, it compares to the nature of their misdeeds and how much they contributed to the art form. I'll discard a shitweasel that has no talent pretty easily. It gets harder when they have amazing or unique talent, because they can offer you an experience or connection that is rare. At that point, it becomes harder to justify supporting them on rational terms.

Kevin Spacey is a fine actor, and very charismatic. But I don't think he pushed the medium in any new direction, so I don't feel all that bad or any great loss about not watching his films.

My moral dilemma is with Mel Gibson. He's an all time great movie star, an amazing actor and a fantastic director. He's also racist, sexist and antisemitic. His outbursts captured on tape are some of the most vile things you'll hear a human being say. But to play devil's advocate, he's also diagnosed with bipolar and has an extensive history of alcohol addiction. So he's prone to poor judgment and wild or unpredictable mood swings, which can include rage. Those outbursts are not necessarily things he's fully in control of. But these are also outbursts that have a continuity over time.

So with Mel, he's an amazing contributor to movie history. He's a rare breed of star, he can play any genre effortlessly, and he's made as a director one of the most truly adrenaline-pumping movies I've ever seen (Apocalypto). I want to keep watching his work. But he's acted abhorrently on several occasions, that I do wonder if I should support his work. The best way I can reconcile it is that he's not always well, and should give him some consideration due to his mental illness. He's also not taken his actions beyond words (to my knowledge). So he's no Kevin Spacey/Cosby/Weinstein with a deliberate, systematic approach to physical abuse.

I think I do draw a hard line at anyone who engages in deliberate victimization/exploitation. Predators targeting people with less power than themselves can just fuck right off.