Utility is better served in the long run by ensuring continued civility. Reduced civility frequently results in the retirement of the best contributors to utility.
Have you read "Evaporative Cooling of Group Beliefs" by Eliezer Yudkowsky[1]? It's the same principle: when civility diminishes and hostility increases, the first members to leave aren't the ones being uncivil and hostile, but the ones who are civil and gregarious.
All you have to do is note that the majority of quality contributors here are civil and polite to see who's going to leave if the civility of discussion decreases.
I am generally civil and polite (though I may not be a quality contributor), but one serious problem I have with HN is the cognitive dissonance between "No humour - we're a mature, civil site" and "Random yahoos can make your comments unreadable, with no reason and no accountability - we're a mature, civil site".
There are several comments in this very post where the user is being civil and polite, yet their commentary is faded out. One of them is even dead.
It leads to a feeling of randomness, and the sense of popularity being more important than insightfulness. On a site dedicated to the mavericks, it's a curious mechanism to enforce toeing the popular line.
To buy in to it I'd have to see some evidence that the hypothesis is supported in groups similar to the population of active users of HN. What I see is that a lot of main contributors are bought in heavily and so are unlikely to leave. It is these users here that are like the group in the article of whom it is said:
"The challenge to their belief presents an immense cognitive dissonance; they must find reinforcing thoughts to counter the shock, and so become more fanatical."
I warrant that those who are most civil, in this context, are those who are effectively 'fanatical' about maintaining the group as a useful communication tool.
Basically the evaporative metaphor requires you to decide who the fanatics are and you can spin this in different ways according to the result that you wish to forward.
