If you guys didn't check out the stupendously organized WriteOnCon, I encourage you to do so, the logged conference perfect for those without funds, time, or social skills (me, the latter).
Despite all the goodness to be found there (agent interviews, author commentaries, etc.), there was one thing that really torqued my jaw. One particular agent offered her time to critique queries via an online chat (full disclosure: mine was not in there). She offered some valuable feedback, but for queries she did not favor, she too often resorted to snark in her criticism (and, unfortunately, all too often, the ogling masses tittered along).
From my experiences, besides retribution, failure and superiority (artificially created or not) are the two largest factors that engender cruelty toward others, and this can be readily spurred on by the mob mentality. Humor, too often in our culture, is created via denigration of those without voice.
In the writing community, failure is a common tattered thread and quasi-superiority isn't far behind (ha, look at that poor schlep's query... starting with a rhetorical question... fool... and let's not get started on agents, gatherers of fawning wannabes who will lap up the milk no matter how spoiled it may be), so, as in comics' circles, we too often flay each other because, hell, we're thick-skinned (we've learned to be via all that damn rejection) and given all our experience (whether failure, success, or just exposure), we've earned the right, right?
If you want to be funny, be neutrally so, or self-deprecatingly so, or, if you must, do so at the expense of the giants to whom you are a mite on their callouses (...yes, I'm trying to vindicate my Stephenie Meyer jests here ;), but don't wreck the voiceless because it's too easy.
Snark, condescension, etc. is pyrite. It can be found in droves. Looks shiny, but scratch the surface and there's not much there. Look at the Nathan Bransfords and Mary Koles of the agent world, agents who have large online followings... achieved through generosity of insight and wit, wit that's sometimes wry, but never inhumanely directed.
As with zoos, don't feed the animals.