One can't codify everything, it's even impossible to anticipate everything.

Let's say we had a hypothetical rule saying that more than 5 insults per day are not acceptable, then someone would insist he only insulted 4.5 times per day and that "wanker" is a normal greeting in Greece.

It's a fine line for admin interventions too.

Me and several others left another board because a (technical) admin started to delete posts criticizing her random "interventions".

So starting this public thread is exactly the way to go...