It’s even more insidious than the power that Reddit moderators have because at least you can see that comments were deleted.
A platform designed specifically around federating giant censorship networks has nothing to do with free speech. The only free speech their is that someone can setup their own instance, but that’s no different than phpbb, which doesn’t make such a grandiose claim about free speech.
It's also untrue that an instance you run will be like phpbb, even if you don't get federated by larger mastodon instances, there are plenty of instances that federate with anyone who's not hosting illegal content or spam. And you can join those instances if you don't want to host.
This is free speech as a principle; nobody has to host you and you get an audience of poeple who are willing to listen. Nobody who doesn't want to listen has to listen. That second part is integral in true free speech.
And I would also point out that Mastodon or Pleroma work just fine federating small networks, they don't have to be "censorship networks", which I think is begging the question a bit.
It's not authoritarian, it's free speech as a principle. You can say what you want and everyone who is willing can listen. Everyone else doesn't have to listen. That is free speech.
You aren't kicked of the platform, you can still be part of the fediverse, in fact, there is plenty of instance that are willing to uphold the "no moderation free speech" fake principle to host trolls and alt-right who federate with everything that is legal.