This is an interesting point. But being banned from a small forum feels like disassociation. Being banned from a huge central platform—the de facto public square—feels a lot less like free speech.

Maybe a better way of thinking about this is that “free speech” on the Internet is about decentralization of small communities even if many of those communities themselves skew authoritarian? If you are banned from a small private gathering, everyone’s practical speech rights remain in-tact. You aren’t banned from the larger system.