1. fuck J.K. Rowling and anything to do with her.

2. you want a Harry Potter themed instance? fucking make one.

People who are part of the Fediverse are generally progressive, which is why they are here to begin with instead of facebook/Xitter/reddit.
People who are progressive generally don't like people who don't like trans people.

This is just anecdotally, but it there seems to be much higher than average rate of trans persons on the fediverse.

There is !harrypotter@literature.cafe if you want to join. There is some activity at the moment, but not enough to go for a dedicated instance.

Also, as the other comments have shown, the bigotry of the author does not help.

1. Your "separate the author from the works" is your opinion

2. Even if we do separate them, the works themselves are brimful of problematic tropes and stereotypes

3. I don't want Harry Potter fans coming here, good god. I'd rather sound with a habanero-infused DS stylus than hang out with Harry Potter fans.

Most of the people on the fediverse are adults who are most likely going to join either a general instance or a themed instance for interests for adults and not for a children’s book series, especially not one with a TERFy author

People like SpongeBob, I don’t think there is interest for a SpongeBob instance. Nevertheless if you think there is interest in it, feel free to host your own.

The issue at hand is you fail to separate the fandom from the economic benefit driven to the author.

It's like buying Nestle because you enjoy the chocolate, despite the fact that there are respectable companies that aren't absolute monsters that also make chocolate you could be enjoying.

JKR is as much HP as Mark Schneide is Nestle. End of story. If you don't support her views, find one of the millions of other wonderful works of literature to be a fan of.

be the change you want to see

It's very obvious that the kind of people that hang around in fediverse absolutely despise Rowling. I never see any positive discourse about Harry Potter here. Even discussions about the game are generally negative.

There was one, but as you can see, there isn't much of an interest in the works of bigots

"separate creator from the art" only works when the creator has passed and no longer benefits from celebrating the art. Arguably not even then.

Well, even if you ignore the author, the books are actually trash once you're older than ~16 years (give or take a year or two). There are soooo many inconsistencies, that I could write like one full A4 page just from the top of my head (and I read it in 2007, so you bet I've forgotten most of it). I could write many more pages with some light Googling.

Why does it have to be a whole instance? Why not just create a community for it and start posting content you find interesting?

Perhaps because there aren't actually that many dedicated Harry Potter fans on the site? It is quite small, and a bit niche as it is now.

Create one yourself. Nothing is stopping you.

95% of the comments is this.

Just let OP have their dream.