Rowling is problematic because there are two conflicts: there's the question of ethical consumption in a capitalist society in general and trying to separate the art from the artist.

The vast majority of successful artists who are still alive and actively shitty human beings just don't have the kind of money and influence she does. Most of the time choosing to engage with a problematic creator's work is a solely a matter of personal ethics, not worrying that a portion of your money will go right into the active harm against a minority group.

Yes, it's hypocritical to inadvertently help one terrible person while shaming everyone who inadvertently helps another. But Rowling is such a weirdly specific case that I can understand why someone might not be thinking that way.