To be clear, not talking about this community, obviously 😛.
What's the point of writing down rules, if mods just do what they want? But I suppose that's the risk you take when you call someone a liar in a small community; they might be a mod.
Edit: I'm not trying to say that mods suck, they perform a useful and often thankless job. Just that it can be difficult for small communities to get a healthy number of good mods, which can become a problem.
You can just call those people buttheads and hit them with short bans until they get the message. Really, you can hand out 3-day bans like candy. It's infinitely more useful than any form of 3-strike punishment game or kneejerk permaban.
I think this is good, as long as the user gets informed a) they they're banned and b) what rule they broke.
A warning first would also be nice, especially if it's in the community rules 😛
Reddit's automatic mesages on mod action were a positive and arguably necessary feature.
But if bans are long enough to annoy and short enough to frustrate, they basically are the warning. Less gun-to-your-head, more spritzing a cat in the face.