I’ve seen people talk about actors and artists that had a terrible time.
My own would be Anne Rice. She wrote Interview with the Vampire after her young daughter died of Leukemia. Then her husband suddenly died of a brain hemorrhage. I suspect her Christian, anti-fanfic phase was a result of mental illness and manipulation from the publishers, although I don’t think she ever apologized.
She was to certain acceptable targets. The most glaringly obvious is probably fat people. The HP books are dripping with fatphobia, both in terms of which characters are fat and how those fat characters are described. She’s by no means unique in this, but it’s glaringly mean-spirited. You don’t write those descriptions by accident.
There’s also a very interesting(perhaps unconscious, on her part) thing she does in differentiating fat-evil and skinny-evil. Characters who are fat-evil aren’t going to redeem themselves, but skinny-evil characters(the ones who are explicitly described as being skinny, to be clear) are more likely to have hidden nuance to them, like Aunt Petunia’s reveal. The most obvious case of this was Dudley’s transformation in book 5, with his weight loss correlating with a change in behavior toward Harry. Oh but the dementor was responsible! Yeah, but what was stopping him from still being fat when the dementor did its thing? Why did JKR make that choice? Could it be that she couldn’t bring herself to introduce that nuance to a character who had previously been described as that disgustingly fat?
Molly, Charlie, Fred & George Weasley were all described as stout-figured in the books. Nobody hates them (well Filch, when they earned it). Neville was also depicted as being round. I don’t have time to list every overweight character on the “good” side; the point you should be able to acknowledge is that she did not make heaviness an exclusively evil trait.
Additionally, most of the antagonists are thin/average. Do you think you’re meant to read them as less-bad people because of that? No, because weight/body type has literally nothing to do with the battle lines.
You should listen to Shaun’s video on the Harry Potter series. He pointed out the meanness towards fat characters and also the way it’s treated differently in “good” vs “bad” characters.