It's not really that dramatic when you consider that a trans teenager was murdered recently and the judge found that transphobia was a motivation for the murder.
One of the killers repeatedly referred to the victim as 'it' in their correspondence.
So yeah, how pronouns are used clearly forms part of the broader picture of transphobia.
JKR may not have commited any crime but she has certainly not done herself any favours.
There were quite a few folk out there who had some time for what she had to say, they've now read the diatribe and the vitriolic attitude is a dawning realisation for them; a 'penny-dropping' moment that this isn't about a common-sense position but a seemingly deep-seated antipathy towards trans people