This bill was obviously created to punish working-class people with less power than Rowling. So, while Rowling may be safe from veritable thought police, that doesn't mean regular people will be able to call a man a man and a woman a woman. This law protects the delusional at the expense of free thinking, and its vague nature seems to have been written so that, sooner or later, both women and men could face charges.
Nothing in this bill states that what Rowling said, or even misgendering more generally, would be a crime. Not only will the police face a high bar when it comes to who violates the law, but the law itself also protects free speech surrounding these exact topics. Just because hateful rhetoric is reported and investigated doesn't mean that the police will actually handcuff people for speaking their minds.