Comment by SwellJoe

Every instance has their own moderation and defederation policies.

And, you might like to look into what that actually means. In the case of mas.to, the controversial decisions include defederation of instances that have a history of bigotry, usually anti-trans bigotry (the kind of bigotry lots of mainstream social sites allow and even protect).

Defederation is a large hammer, so some folks think mas.to is too strict. But, I personally prefer no slurs or child porn in my feed (adults posting nudes of themselves with a content warning is fine, both by my reckoning and the policy of mas.to), so I've never had reason to complain, nor have I ever had an interaction with moderators.

X is far more censorious than Mastodon of the kinds of free speech that are actually politically meaningful, so I'm surprised you call it out specifically as your free speech safe space. But, if you mean the same thing Musk means when you say "free speech", the right to punch down with impunity, perhaps X is the right place. Punching down is exactly the kind of thing that gets you banned on many Mastodon instances. It is a place that is by and large extremely intolerant of intolerance, but accepting of most everything else.