No, the fediverse has at least one per instance, often more. I would even go as far saying the fedi has more mods per users. They're still only mods, for the instance they're on, though.
I saw pornography of very dubious legality within seconds of opening a public Mastodon server during my first time checking out the fediverse. It was enough to convince me never to use Mastodon again.
And I saw pornography on Twitter, which obviously IS THE ting Mastodon copies, too. It totally depends on the instance's mods what they allow and yes, mastodon.social allows porn. Mastodon is not a social platform for catholics. If you see porn without NSFW Content Warning, you can report it.
