It’s hard to understand how or why Rowling believed publishing this book would be a good idea.
It doesn’t even make sense from a crass marketing point of view. Even if all the controversy were to stir interest and drive book sales, which is far from a given, it wouldn’t make any difference to her financially.
Her other books published under pen names have never sold even a significant fraction of what her Potter franchise books sell.
She doesn’t need the money or the publicity. She’s doing this because she wants to.
She’s doing this because she thinks she has something important to say.
Which is all the more tragic and infuriating.