You’re in the UN or you’re not, bad behavior of a server gets you kicked out of the UN.

Someone described the fediverse as the social media of email.

You make an email account with any provider you want and you can talk to any other email in existance.

You make an account with any federated site you want and you use it to access and talk to any other federated site in existance.

Well, GMail and other proprietary providers also blocks certain domains.