Yeah reddit is unique for it's layered self-regulation by users at scale.

Upvotes/downvotes, complaint comments, volunteer user mods, at the end of the day automod is still set up by users. Then on the top layer you have admins.

That's not to say content in people's feeds are entirely down to upvotes/downvotes. Reddit Inc. does use an algorithm to give preference to certain communities, and they've done it from near the start. IIRC in 2011 a data engineer looked at the reddit API and when reddit's code was on GitHub and replicated the results. He noted that some meme subreddits were a lot lower than what would have happened if it was just based on upvote/downvotes.