It's not the first time I've heard that idea. I recall a comment once in which it was claimed that JKR said that if she were a teenager in the present time, she would probably have transitioned. Unfortunately I could not find any source for that claim, but given just how insane she's been on the matter, I wouldn't be surprised if there was something going on there. Same for Linehan, honestly.

Personally I would forgive her, IF that turned out to be true, AND she made a public apology for everything awful she ever said, AND threw her financial weight behind actually fighting for trans rights, AND opened a school or something specifically for disadvantaged trans kids, and kept doing such things to the point that it actually made a positive impact, then I would say she had redeemed herself.

But I'm not holding my breath for even one picosecond, thinking that it would actually happen.