The foundation of free speech is that you cannot force someone to say something they do not want to. This is a lot more foundational than the “you can say what you want” aspect of free speech. You can’t force someone to agree with you, you can’t force someone to publish or say something in their name, you can’t force someone to host content on their website.
Similarly, you can’t force an owner of a Lemmy instance to host or say something they don’t want to. If an owner said “you know what, I don’t want to host this” or “I don’t want to federate with X” then you can disagree with them sure, but you can’t force them to say/do something they don’t want to.
Whether this is or isn’t authoritarian, the alternative is that someone can force a Lemmy owner to host things they don’t want in their server. Imagine if some really repugnant communities showed up on your instance and you couldn’t remove them. Now that really would be authoritarianism - it’s removing your freedom to choose what you say… Just because someone can say something, doesn’t mean you as an owner/individual have to listen to it, like it, agree with it, or host it.
The big free instances are running off of good will, they don’t owe you anything, they certainly don’t owe your view a voice unconditionally. If you don’t like it, especially with Lemmy, you can set up your own instance/club and say and not say what you like.
The heck is a “free speech” phone? Very few phones prevent you from unlocking the bootloader and putting whatever software you want on it. The problem is what software do you want?
If you’re concerned about Google snooping on you, first off, get an iPhone. (They are marginally less snoopy, but it’s still not great.)
If you’re concerned about stock android, buy any smartphone and put Lineage or Graphene on it. You can then install Google’s services on it if you want (play store!), but at that point I’d save your time and stick with the normal version of Android that shipped with your phone.
If you’re really concerned about FOSS and having control of your device, put a Linux mobile distro on your phone - see here. Be warned, even the best mobile Linux distros are miles behind Android in terms of usability for the average user. If you want to go all in on open source, get a Pinephone or Fairphone and put Linux on it.
As a note of caution, lots of people (including me) think they want a FOSS device until they have to use one. You can totally go FOSS and fully libre, but it does come at the expense of convenience. I am quite happy with my pixel with stock android and all of the convenience that provides, but each to their own.