This reminds me. There was this discussion about the play that Rowling wrote instead of an eight book, 'The cursed child' I believe I did not watch it. If I remember correctly, I complained in the forum about Hermione being cast by a black person and a bunch of people said that this was racist. I feel like going back there now.
I think the main issue, as it so often is, was that no-one specified what question is being debated. As far as whether or not it was a good casting choice, at this point my probability distribution puts significant weight on 'this was the only right thing to do from a utilitarian perspective, and anything else is passing on an opportunity to create a uniquely meaningful empowering symbol'. I also certainly don't think it was done cynically. Most likely Rowling's intentions were pure. And I'm genuinely unsure about how strong of an effect it has.
What annoyed me back then and still annoys me now is her saying on twitter 'being white was never specified' for hermione. Aside from this being like 70% untrue because harry could see her 'white face from behind a tree' or something (( I precisely know where this scene is the German book and even have clips of the audio book in my head, that's how often I've listened to them )), the idea that she thought of her as black from the beginning is just such utter bullshit. If would be cool if she had, but she hasn't. I don't want people to lie. Sam Harris talks about this; you can get by without lying almost all of the time.
What she should have done imo is to just tell the truth: "I created this famous story with three white main character because [whatever the real reason is], but I think it's more powerful to re-imagine it this way, and it doesn't contradict canon too much so you don't get to complain". I would give her so much credit if she had done that. If the problem is that we default to white-male-main-character-with-close-friends-white-and-at-least-half-male, then admitting that you did that and want to change seems to me like a more powerful message than pretending like you intended this in the first place but decided to never provide evidence for it anywhere.
Then of course it's possible to think her twitter post was good for strategic reasons while admitting that it's dishonest. Maybe she thought she had to lie because it won't seem as real if she admits she thought of Hermione differently. I don't really think that's true, though it's possible. But in any case, doubting that it's dishonest is ridiculous. And actually I remember talking to Space about this, who takes this kind of stuff very seriously. They argued for the utilitarian effect but admitted immediately that Rowling didn't think of her as black while writing the books.
Anyone feel free to debate me on this take.