This I really like. On another forum I moderate, we used to have a pretty bad attitude to most members because a majority of the posters were, to be fair, less than reasonable. As soon as we implemented a system for rewarding users for appropriate posting (badges system, special ranks, etc) people were much easier to deal with, and seemed to care about their own stature from then on. People wanted to post well to be rewarded these items, and continued to post well to keep them. However, we still needed to resolve our own issues. For example, not going off on someone for a bad post, and instead kindly requesting they fix their behavior (in a PM if possible). This normally ends in the situation being dealt with nicely, but on the occasion they didn't, they got 'warned' or banned depending on the case at hand (we have an auto temp-ban system after 3 'warnings').
I genuinely don't think there is ever an appropriate situation for a moderator to openly say "Fuck you, stop posting" to anyone in a thread. That's entirely no way to set an example, and could only serve to further irritate the person posting, or get m@d pr0ps by other pretentious members (either intentionally or unintentionally) and get the message sigged by them or something equally idiotic. Even if you need to call someone out on their behavior, a PM would be ideal. If they still don't adhere, an infraction seems plenty acceptable.
Gonna be honest, though, I think this is a good thread with a lot of potential-- of which it already has-- to receive feedback and I'm glad it hasn't been locked. Been feeling like saying some of this for a while now.