Despite its genuine decentralisation, Mastodon has also implemented a server covenant that does a pretty good job of excluding the far-right extremists by a purely social process — if you keep horrible arseholes on your server, you’re liable to be shunned.
This has led to a “dark” Fediverse of sites that don’t go along with the covenant but still talk to each other. Gab is such a site, for example.
If you want untrammelled free speech social networks, they’re right there, right now!
For some reason, neither Pirate Wires nor Dorsey are interested in these existing real-world examples.
This is because these guys only care about their assumed right to force people who aren’t interested to listen. “Free speech” is when they can say awful stuff and you can’t answer back. When Dorsey calls Twitter — Twitter! — “freedom technology,” that’s the freedom he means. They can’t live without unwilling ears to bash.