Someone else more less touched on this but I think you’re missing the point.

I don’t know a single person who thinks you can’t like someone’s art because you dislike the artist. Using your example, I have plenty of friends who grew up with Harry Potter and still absolutely love the series in many ways. However they also think JK Rowling is a piece of shit.

The problem lies in giving a platform to people who, at the very least outspokenly, espouse harmful views, and/or engage in harmful activities. So generally speaking, they tend to take some amount of issue (how much varies person to person) with people continuing to support works from them without some demonstration of change or betterment. In turn, most of us stop consuming their content wholesale, as we don’t want to support their actions or views by contributing to their platform and would prefer others do the same.

People like what you’re talking about exist, sure. I also think that demographic is nearly exclusively terminally online people, who tend to be quite a bit louder than your average person. Which in turn can skew how commonly held of an opinion something can seem to be.