I dunno. I'm an autistic anxiety-sufferer who scours subreddit rules before I ever try to post anything, specifically to avoid the embarrassment and shame of doing it "wrong", and some of those subs are still impossible. Have you ever tried to post anything in r/Showerthoughts? The rules absolutely don't cover all the things the automod will instantly remove. It uses some kind of keyword tagging system that is never explained in any of the sidebars or wikis. I tried maybe a dozen different thoughts over the course of a couple months and not one of them got past the automod (well, except for the one that a mod reposted as their own 24 hours after mine got deleted, but that's gotta be a coincidence).

Or, my second-favorite, the one where your post gets autoremoved for "Rule 4", but there's no list of numbered rules anywhere on or linked to the subreddit. I think that's a "feature" of New Reddit, where Old Reddit users can't see the sidebars anymore under certain conditions, but I'm not sure.

And then, third favorite, are the ones OP is probably talking about, where the rules amount to a college textbook's worth of pages that have been through no developmental editing or copyediting, so they're more vague than 5e's description of the Magic Jar spell, but whatever interpretation the mods are using, it's not the obvious one... or the second-obvious.... or the third-obvious...