> pretty narrow

Not so for better or worse. Multiple people have been banned from Twitter for calling a human rights litigation troll (and Twitter troll) a man (he is male).

https://nationalpost.com/news/free-speech-activist-lindsay-s...

https://mobile.twitter.com/bindelj/status/118726943929891225...

Calling a male troll “he” is definitely not illegal, yet you can be banned from Twitter for it. It’s not an incitement to violence, it’s not even borderline. Meanwhile that troll can ridicule one of the women in question for having a reproductive abnormality, so go figure. There’s a lot Twitter will ban you for that’s not remotely illegal, the gap is wide.