I think this is what frustrates a lot of TRAs (and even a lot of younger people in general, who've had it drilled into them that anything other than unquestioning acceptance of anyone identifying as trans into single sex spaces is bigotry).
They can say that wearing or buying Harry Potter merchandise is a visible indicator that a person is a bigot. They can say that buying Rowling's books shows that a person supports the genocide of trans people. They can scream until they're blue in the face how Rowling is an old hag who's a self-hating trans man infected with mold.
But, ultimately... it has no effect. Harry Potter is still a huge franchise with massive backing from both publishers and film/TV studios. New generations of children are reading and loving the books. Lego still release masses of sets, people flock en masse to the studio tour. Kids (and adults!) still wear t-shirts of the Hogwarts houses. And companies promote their Harry Potter doughnuts.
The Cormoran Strike books still do incredibly well, there's still TV series being made (The Running Grave is expected to start showing this December).
JK Rowling is still a billionaire, despite donating hundred of millions to charities, including one's helping single mothers, children in poverty, domestic violence victims, multiple sclerosis sufferers, refugees, Afghan women fleeing the Taliban, as well as her well-documented support for gender critical feminist organisations. She's one of the country's biggest taxpayers, because she doesn't hide all of her wealth in trusts and offshore accounts.
Screaming unhinged abuse at her is all they have, because nothing they say or do seems to materially impact the popularity of her work, and certainly doesn't impact her bank balance... because most people don't think it's unreasonable to say stuff that's basically, "biological sex is a scientific fact, and single sex spaces/sports exist for a reason".