Some things I agree with here, others I disagree with. JKR is not, and I suspect never will be, a great writer. I'm a mediocre writer myself, and it takes one to know one! Her writing at it's best is clear and readable, but no more than that. Her world-building, in a post-Tolkien era, is slapdash at best. She creates and leaves gaping, more plot-holes than a Marvel comic printed on lace. She relies on massively- contrived, credibility-straining plot devices and a great deal more.
What she did with Harry Potter was to create a welcome atavism. A childrens' story without an 'unreliable narrator', without a bleak urban background, with only two dysfunctional families (the Dursleys and the Riddles). A tale that harked back to the halcyon days of the kids putting one over on the grown ups when it came to beating the bad guys. At the core was not a set of left-wing principles, but friendship, pure and simple. The unbreakable bonds between her little Scooby Gang - Voldemort would've got away with it if it hadn't been for those meddling kids! It gave kids what they wanted, instead of what critics and commentators told them they should want. Result, runaway success!
But as the Christian Bible has it "When I became a man, I put away from me childish things." The core issue here is adult fans who have deeply internalised their own concept of what the story should be about, instead of reading more adult books and drawing their politics and philosophy from them.
Somewhere, we are losing a vital process. A process whereby the child becomes an adult and changes as they do so. A process called, I believe, 'growing up'!