Maybe it is? Don't non-binary people have a right to moderate their own space as they like?
If they have a rule against gatekeeping gender identities and pronouns in their own instance, don't they have a right to remove offenders from their servers?
You're all over this topic today, maybe just take a second and listen to what the community is saying. You've more than said your piece.
I have a related question:
Where do the users who get banned from YPTB go, when they eventually get banned from YPTB?