I mean if the mods want to run their subreddit as a dictatorship that's allowed, and having a public log wouldn't stop that. It just means that you can't pretend you're not intervening if you are.
Yes and no. Like, is there a guy who decides who to kick out of the intramural softball league? Probably yes. But people will see that it's happened and talk about it, and if it was unreasonable then at some point they'll have a word with the guy, and maybe oust him or start their own splinter league or what have you. All of which is sort of possible on reddit up to a point, but those mechanisms are much less functional because the only community interaction is the subreddit itself where the moderator can just silently remove any posts they don't like.