If people want to call her to be #cancelled they can I guess, but it's never gonna actually happen. Potter Mayhem is far bigger and largely beyond her now. At best, her future books will likely just not have the fanbase behind them.
And I think this issue is different to the vegan/vegetarian thing. In this matter, Rowling is actively supporting someone who wants laws changed that protect trans people as the Equality Act in the UK gives them the same rights as anyone else to not face discrimination. By changing this, she is actively campaigning against them and for the erosion of basic rights which future people will want to use to allow them to discriminate against people because of sexuality/race as well.
It isn't about her not being "fully progressive" but an active opponent at this point. She is actively calling for less rights and is making her stance as enemy of trans people known. If she was simply dismissive or doing nothing, that would be entirely different. But in her efforts to "support women" she has shown she is willing to step on the little guy she has long claimed to support.
fair enough. I don't know anything about rowlings beliefs except people were acting like she was super progressive before, so I was just going by that assumption