You're equating subreddits to forums but on forums people recognised other posters and the average subreddit poster will never read the same username twice, if they even notice they're there.

I see the argument you're making, but it's not convincing. These just aren't similar types of social engagement.

> The current top comment isn’t there because it’s the most recent, the only objectively correct one, or a mod pinned it. It’s there because the algorithm driven by social engagement decided it’s the media I should see first.

When people neglect to vote that they like the comment you posted, or they vote that they didn't like the thing you posted, this is algorithm driven by social engagement.

When the forum software which sorts by newest-posted-first bumps your thread off the front page because no one cared enough to reply that was also an algorithm driven by social engagement.

It seems a lot to me like the "hidden algorithm" part is the same? It is still the users indicating more/no more in the end.