Ok, so? People block you all the time because they don't agree with you, why is that a problem? If people don't want to hear what you say, shouldn't they be allowed to not listen?
Personally, I don't understand that point of view of blocking people who you disagree with, for me the point of the internet is to find different views and perspectives, but I'm also fine with others filtering out whatever I say, doesn't really impact me either way.
If you want no rules what you say, run your own instance. Depending on what you say, some people will want to listen, others will want to filter your opinion away, I don't think either sides are "wrong" for that, it's just like in real life. If you want to use someone else's instance, you follow their rules. It mostly isn't harder than this.
You go on a cruise for two weeks and there's a disagreement about whether to federate with Meta or not. Your admin takes a side, whatever that side might be. Two weeks later, you come back and lose 10% of followers, and there's nothing you can do about it.
Nobody chooses instances for that, very few know anything about the admin, people just like the content until... in >70% of cases, bait and switch follows
That's why Mastodon is such an incredible mess, it creates the conditions for serious problems, then goes: "you chose what you knew nothing about, nor there's any way to know anything, therefore... you are the problem".
I've heard of instances carrying a lot of Nazi content being banned, and of instances choosing not to re-host adult media (which makes the interface a bit worse, but doesn't actually block you from getting that). But most admins from what I've seen are pretty clear on this in the about page of the instance.
70% seems like a wild claim.
I have had content I like being removed from major social media platforms, like reddit and tumblr.
Also, if you choose an instance and it gets shut down, you just start another account. This isn't serious business, it's social media. To me, complaining about having to choose an instance to start is like complaining about having to choose a class at the start of an RPG.
Personally, I really love mastodon as a platform and I don't understand all the hate it gets here.
... wait a minute.
In case you haven't read them before, the docs for migrating are here: https://atproto.com/guides/account-migration
Ahckchually, once you create an account you can use the API endpoint for remote lookup to test in an automated manner which nodes are and aren't reachable.