Having a difference of opinion with Rowling is one thing, but actually HATING her for holding an opinion and daring to express it? Yes, I think that's creepy.
I don't know. I mean, its one thing to not agree with trans people having rights, and another to use your platform to basically spew constant hate at them. So, I would loathe her actively, except she's not worth the energy.
Besides, she's really a hack writer. She wrote the Harry Potter books, finished them, then changed her mind and tried to say that the wrong people ended up together. But mostly, she hurt an awful lot of vulnerable people - kids included - by being so rabidly TERF. Not to mention, her parroting the whole 'Only people with uteruses and periods are women, which hurt me on several levels, and lots of other people too, I'm sure.
So, while I wouldn't bother trying to attack her, nor try and get anyone else to either, she can go fuck herself with a rusted steal cactus and the world would be a better place for it.
And if you think thats creepy, fine, but I find calling it simply a 'difference of opinion' up there with calling fascism just a 'difference of opinions; both far more damaging and creepy than hating someone for either.