Nobody is being “forcibly” silenced. They’re still free to exercise their first amendment rights on their own website, in public spaces, friendly private spaces, etc.

What they aren’t is entitled to force a private company to host and promote their content.

Precisely. And that's what people already do when mainstream social media sites won't host their content. Meaning you can't stop misinformation from spreading, not this way. If anything, you're achieving the OPPOSITE effect by turning people who get cancelled into "martyrs".

And by "forcefully", I meant between the walls of the specific media site. (Though good luck explaining the difference to an angry mob.)

You’re missing a big key concept: Trump wasn’t on Twitter because he couldn’t afford a website. He was there because it gave him a much larger audience than would otherwise seek him out. The right-wingers who complain about the terms of service being enforced are doing so because they know they aren’t going to build anywhere near the audience without considerably more work and time.

It probably won't, but it makes it harder for such narratives to reach other people that may otherwise get radicalized.

Reducing the audience of these narratives can help with reducing their impact. I don't think this is a great solution, but not having people locked into alternate realities in the first place does not seem naive.