My belief on this is simple: if you can stomach that the creator of whatever art you're consuming might not be a good person and they believe this or that, then I don't see any real problems. Of course, you can say in cases like with JK Rowling and her transphobia and other gut-wrenching beliefs taint HP, but you could also say that they don't ruin the magic one bit.
Personally, I can still very much enjoy HP because, much like Butch Hartman's works (if you know you know), it has become bigger than her.
Now there are definitely cases where I just cannot do this. Lostprophets, for one, are forever ruined for me. What the lead singer did just leaves a bad taste in my mouth for very obvious reasons, especially any time I think about listening to any of their songs. I was never much of a Kanye fan, but after what he said as of late, I never will be now.