Is it possible to have a public forum without moderators?

Like, I keep seeing reddit moderators abusing their powers but rarely they suffer consequences. So I’m wondering if there’s a way to have a public forum without moderators.

That’s called 4chan. You can make a version of 4chan on the fediverse but good luck keeping your hosting providers happy when the content stored becomes more and more vile (just read their wikipedia page to find out their troubles with that)