On Mastodon, people can choose to pick an instance that will rarely defederate anyone and follow or mute on an individual basis, or they can choose an instance where moderators will take a firmer line.
>>vidarh+(OP)
The trouble is how to judge them. Automated censorship of others is invisible unless they announce it or you somehow know what you should have been able to see.
>>tinus_+Ia
If you choose to only talk to like-minded people, that is your right, as it should be. And might well be one of the reasons most people aren't on Twitter, and many who are subscribe to extensive block lists.
>>erik_s+kb
Mastodon instances tend to have admins who are if anything pretty loud and argumentative about what their mod policies are. If that matters to you, you can easily find instances that make a point of being open about what they block. A whole lot of people don't care about the how or why as long as they're not subjected to content they don't want to see, and that's their choice.