Yes. You can absolutely hate a person and still have an appreciation for art that person has created. The angst about JK Rowling in particular is an easy public performance. It requires no real effort to say "Yes, I hate her too, she bad!"

On the other hand it takes an awful lot of effort to research everyone involved with all of the media you consume to make sure you're not enriching anyone who holds similar views. So you almost certainly don't put in effort to make sure you don't enrich anyone with shitty views, because it's not something you genuinely care deeply enough about for it to be worth changing your life and habits and putting in so much work. You just want to be able to say "See, I'm one of the good ones and fuck the bad ones."

That's the difference between separating an artist from their art and performative virtue signaling. I have no problem supporting art that I genuinely love that isn't made by flawless, divine beings. If I find out the people are shit I'm willing to accept that and not like the person, but that doesn't change my enjoyment of the art itself. The art is not the person.

If I take my car to a mechanic who does a wonderful job fixing it up and the car now runs like a dream come true, and then I find out he stabbed someone once, I'm not going to suddenly start hating what a good job he did professionally. That was still a good job. Me appreciating that isn't condoning or supporting stabbing folk. I won't feel the need to loudly proclaim that he's awful and I hate that I went to him and I'd take it all back to show you and other people what a goody good person I am. Because I don't care what you think. You're irrelevant. I'm absolutely fine with idiots thinking I'm a dick. I'm an honest one. Most of you are full of shit and putting on social theater. I find that far more disgusting than being an honest dick.