It isn't even that JKR said "transphobic" things. If I recall correctly, she just wanted to protect womens' rights.

"Women should not have to share bathrooms with predatory males" is absolutely not the same thing as "trans people need to be wiped out!"

But part of this is her own doing. She bowed a few times to the dangerhair mob when she should have just ignored them and continued writing her books. Kissing narcissistic butt is how we've ended up in a lot of this turmoil.