that's because Microsoft said it would blacklist 2b2t (making the client refuse to join it, or the auth server refuse to auth players for it - a punishment normally reserved for pay-to-win servers but the bar has been lowering) if it didn't ban swear words in chat
Considering no other server has to ban swear words (ignoring Bedrock partnered servers), I do not believe that happened. The server administration does not care so they are just trying to censor as much as they can automatically so they don't have to manually spend time looking at the server.
There are other servers who are small enough to continue to have actually anarchy and who are willing to require having alternate domains to bypass the blocks.
"Minecraft Online" painted a target on themselves by choosing that name. They're a walking trademark infringement and a particularly egregious one at that, to the point where they sound like scammers. They got away purely based on goodwill from Mojang.
