Yep. I do reckon there's a percentage of transphobes who are imagining hordes of men pretending to be women to get into women's spaces, but genuinely do have no problem with actual trans people (even in women's spaces. Even as a trans person, I think the belief that, for example, the small number of convicted rapists claiming a trans identity need to be far more closely scrutinised than someone with no history of acting in bad faith, is reasonable.) Now that Rowling is saying the quiet parts out loud, she becomes repulsive to that particular group.