So, I feel I should preface this by saying I've only ever interacted with the original HP-novels (not including whatever that 8th one is called) and the bare surface of the "wizarding world" before deciding the latter was a dumpy worldbuilding nightmare. Thus, my arguments are only concerning said novels.
This, combined with "tone-deafness isn't necessarily deliberate maliciousness" is why I tend to disagree with people saying she's a bad writer. Some of her personal views are.... divisive, to put it politely and forum-friendly, but her actual writing in HP is generally about as good as it has to be for the target audience of the novels. Elements like e.g. the House-Elves show some pretty notable tone-deafness on her part, and the worldbuilding falls apart once you start picking at it, but it fulfills the function it has to: allowing you to immerse yourself in the magical castle-school as a kid/young teen and letting your youthful suspension of disbelief take care of the rest. It's also why I think it falls apart more towards the later novels: they "grew with their audience", but her writing skills weren't quite growing along.
tl;dr From what I know of her viewpoints (again, won't discuss them), there's plenty of real complaints to make about Rowling without analyzing a series of children's novels as if they were mature fantasy works, rather than kid-focused British boarding school fiction in a thin fantasy jacket.