As a rule you go with politeness and live-and-let-live, but JKR was discussing characters, some of them criminals, who 'push it' in a manner hostile to women's rights, making their actual sex the issue. Police Scotland have blinked first and said they definitely won't be charging JKR. Although it's not a judicial precedent, it should mean that 'misgendering' cannot in itself be criminalised, even if you don't have JKR's profile and resources. She's performed a public service by establishing that straight off.
https://www.bbc.co.uk/news/uk-scotland-68712471
The law is still a bad, stupid and unnecessary one (there is no such 'rising tide of hatred' as the Scottish First Minister claims -- the wee laddie's far too young to remember the 1970s, a more difficult time in all sorts of ways), and the police don't welcome it and don't want the pointless workload.