You make it seem like this is an epidemic of silencing.
First of all, this was 7 users. Secondly, it was such a controversial request that it had to be escalated all the way to the country's Supreme Court. Thirdly, the request and its consequences were then reevaluated, and all 5 members of the Supreme Court review unanimously upheld the decision.
There's obviously no such thing as a perfect system, but that is about as close to a fair review process as one can get, and I would argue it's better than the alternatives of "the whims of the platform owner" or "completely unmoderated anarchy".
Furthermore, they're NOT silenced. This is deplatforming. Absolutely NOTHING is stopping these 7 people from setting up their own Mastodon instances and writing whatever they want. That's not an option for the jailed dissidents X turned over.
Lastly, Brazil is a sovereign democratic nation within its rights to enforce its laws as it sees fit within its borders, and if the people find it that egregious they can change their leaders. X is an unaccountable cudgel of a single man who is taking it upon himself to conduct his own judicial review of the laws of a sovereign nation and act with impunity. If he were a nation, this would be an act of war. The sheer gall of it is utterly appalling.