I moved the big meta-level comment thread from "Yes Requires the Possibility of No" over to here, since it seemed mostly unrelated to that top-level post. This not being on frontpage also makes it easier for people to just directly discuss the moderation and meta-level norms.
I'm not sure what your hobby horse is, but I do take objection to the assumption in this post that decoupling norms are the obvious and only correct way to deal with things. The problem with this is that if you actually care about the world, you can't take arguments in isolation, but have to consider the context in which they are made.
1. It can be perfectly OK for the environment to bring up a topic once, but can make people less likely to want to visit the forum if someone brings it up all the time and tries to twist other people's posts towards a discussion of their thing. It would be perfectly alright for moderators who didn't want to drive away their visitors to ask this person to stop.
2. It can be perfectly OK to kick out someone who has a bad reputation that makes important posters unable to post on your website because they don't want to associate with that person, even IF that person has good behavior.
3. It can be perfectly OK to downvote posts that are well-reasoned, on topic, and not misleading, because you're worried about the incentives of those posts being highly upvoted.
All of these things are tradeoffs with decoupled conversation obviously, which has its' own benefits. The website has to decide what values it stands for and will fight for, vs. what it will be flexible on depending on context. What I don't think is OK is just to ignore context and assume that decoupling is always unambiguously the right call.