It's human to want to simplify a complicated situation. It's human to want to believe that people who are more ethical, or more attractive, must be more talented. From where I'm sitting, these are completely disconnected variables. (If there are studies correlating them, I'm unaware of them.) But when an artist people like turns out to be a bad person, it seems like it's easier to decide their art was bad all along than to accept the broader idea that terrible people can make excellent art.
Conflating everything about a person into a single "I like them" or "I don't like them" variable makes it harder to accept that a talented, attractive person who knows all the right gender words, can still be a bad person. It makes you more likely to, if someone made art you dislike, to look for reasons to believe that they're a bad person too. It makes it difficult to accept that a bad person can still do good things, or that a broadly good person (like you, perhaps) can do bad things.
It is crucial to recognize your own capacity to do evil, or you'll never recognize when you do it and never learn to do better.
For the record, though, I never cared for Harry Potter. Just, speaking personally, y'know, never really liked it. Just sayin'.
