No protection for anything. You can post anything. Individuals may block you if they don't like what you say. There's no central servers or admins that can block, ban or censor you.

There are groups you can join. If you're interested in movies, Ford V8 engines or land rights for gay whales, you'll find like minded people.

One problem, or benefit, depending on your view, is there's no algorithm to push things to you. You have to explore and discover shit for yourself.

Nostr requires more effort by you to find shit you're interested in than other social media. But, it's worth the effort.