J.K. Rowling Writes about Her Reasons for Speaking out on Sex and Gender Issues - J.K. Rowling
I don't have the tools to evaluate this, but while she says she supports trans people she says some red flags (bathroom predators in particular) that make me think this isn't in good faith. At the same time I'm always hesitant to use a blanket term like "TERF" because it's often inaccurate... and as a cis straight dude it's kinda not my place to make that judgement. Hrm.