Mods are getting too trigger happy? In fairness if you give random "trusted" strangers power to delete anything they deem inappropriate they will start abusing their power, that's in human nature.
But to them they're not abusing it, they're just interpreting the rules very literally and strictly.
The problem is that any gameified system, like a karma or reputation system, attracts people good at interpreting rules strictly and finding efficient ways to exploit them. So you're actually selecting for literalist rules lawyers.
Last time this blew up on HN, some of the principals of SO turned up here, as did a bunch of mods. They were mostly unable to discuss the issues in terms of serving the audience; they just kept falling back on The Rules. An attitude, I'm sure, which quickly drove off anybody with common sense. So now they have achieved glorious groupthink: everybody they normally talk to agrees with them about The Rules.
Apart from giving them a feel of a power, what does the fact of closing a thread (whether legitimately or not) give to the mods? Do they have some karma incentive to do so?
There's no incentive in closing a question, other than helping the site reach it's goals, and the primary goal for any Stack Exchange site is useful, not interesting or popular (not that they are mutually exclusive, but also not to be confused).
This specific question was turning into crap fast, with answers like "Sounds like your friend is a bit of a dick. Noone wants to work for him." (since deleted). Closing it only prevents further answers, as it was obvious they were deteriorating. Still, the closure and any closure, is reversible, people always have the choice to vote to re-open if they feel the closure wasn't justified.