So much here that is completely upside down untruths.
India can think of himself any way he pleases. He can see himself as a woman, a dog, or a blue felt-tip pen. Or anything else. His own delusions are his own delusions. However, he is, has always been, and will remain forever a male. That is material fact.
Well-adjusted, psychologically health adults are able to recognise facts and the world as it is,and operate to facts and the world as it is, not as they would wish it to be. We can’t let fantasy rule.
India is male. A member of the oppressor class. And a middle-class, white male at that. Quite literally, a member of the most privileged group on the face of the planet. He doesn’t get to tell a lie that acts as a magic wand to get the rest of us believing he’s the underdog. You might buy the lie. More fool you. I’m not so gullible.
Quite how you can possibly assert (presumably with a straight face?) that trans people are very much oppressed is astonishing. Where do you live? Because in the UK and much of the western democracies at least, trans people have held a disproportionate amount of political power for some years. Despite being a tiny majority, they have managed to appropriate extra rights, over and above the rights enjoyed by others of their sex. If you feel opposite, open your eyes and ears.
Moreover, by allowing males to appropriate womanhood, actual women - the actual oppressed group - have seen their rights and safety eroded.
Try using your intellect instead of overly-emoting with the oppressors.
And no, JKR is not widely derided. Are there pockets of lefty-types (of which I am one), who see it as part of the Omnicause to hate on JKR? Sure. There are some who actually believe as you do. Who favour emotion over fact (but only when that emotion and emoting is focused on centring males, not females). But the majority don’t. Lots of people recognise misogyny when they see it and it’s clear to them that deriding JKR for her tone falls squarely within misogyny. Shame you don’t see that.
Edited for typo.