You misunderstand. Being banned from a Mastodon instance doesn't mean you disappear never to be heard from again. No one is going to try to murder you. You're still allowed to participate in society and communicate. Also, the "correct worldview" in this context means not being a racist, bigoted, anti-Semitic asshole. If you find that too much of a straitjacket on your personal liberties or radically free-thinking beliefs, there are Mastodon instances that will happily accept you.
Of course, not everyone, everywhere is compelled to accept you and your speech with open arms, nor should they be. Freedom of speech and freedom of association are equal and opposite.