Unfortunately, that never is the end of it. Again, certain people are oversensitive and respond to completely civil and good faith requests/criticisms/etc with over the top behavior/accusations (see this thread for example). It's part of HN's CoC to avoid saying things that you wouldn't say face-to-face to another person.. on divisive topics like this, it usually doesn't work (again, see this thread) unless someone with the admin bit steps in to remind people to behave themselves and occasionally hand out a vacation or two.
The problem is that you've taken something that is inherently subjective to each and every person and tried to codify it. People do exist that hate being told "no", that hate all forms of disagreement and treat those who regularly do so as enemies to be destroyed. Given a vague legal method to retaliate, how do you think someone with such an unreasonable mindset will behave?
Also, it's possible to be a complete and utter asshole without ever being uncivil. I've been witness to enough Wikipedia politics over the last 5 years or so to make that declaration.
But anyways, you've just begged the question. It's not a given that the absence of CoC's results in "shouting matches", or for that matter, that their presence prevents them. In my own anecdotal-as-hell experience, they don't chase away anything but the most brash of assholes, it just results in a thin veneer of pseudo-civility over the same old crappy behavior and mindsets.
It's a lot easier to eject loud and visible assholes than the stealth ones! In other words, I think it's better to have "Don't be an asshole" as an implicitly understood element of any social group, with implicitly understood punishments for breaking that norm, rather than codifying it in such a way that it gives people ideas as to how it can best be twisted and abused.
(And should it come up: Yes, I find being accused of "sea lioning", whatever the hell that means, to be highly offensive and over the top.)