I believe the term you're looking for is 'douchebag'. It really seems like there are two major issues here (with the player base?). People will throw the term elitist on ANYONE who calls them out for being under geared. They don't have to even be a jerk about it. This was illustrated in another thread where an AF DRG found his way into HM Titan, and was asked to leave as he was severely under geared, and people came to the thread to accuse the person of being an elitist. Then you have those douchebags that have invested copious amounts of time in the game already and act like they are superior to everyone else because their gear is better, and give people a hard time because they aren't as 'leet' as them.
I've got a near full set of Darklight gear (woopdie-doo), and do I get annoyed when someone in AF1 and an Ifrit weapon stumbles into a Garuda run? Yeah a little. Do I get even more annoyed when this clearly under geared player also fails the mechanics, essentially making it one DPS less in a DPS heavy fight? Yeah, a little. Do I act like a jerk and rage at them for it, showing how superior I am? No, because I'm not a douchebag, and in reality, my gear is better. I don't know them any more than I know the next set of pixelated dots; how could I be 'better'(or worse) than them?.
Does this criteria make me an elitist because I expect people to put in the time to get geared for the content they are attempting, instead of stumbling into it because "I got my HM Ifrit weapon and now it is time to upgrade to the HM Garuda weapon!". Incidentally, we did almost clear that fight, but the other 3 DPS were in full Darklight sets...
When they add gear checking on dungeons/raids, these issues won't exist as much, because the circumstances won't occur any more, because if you aren't geared enough for it, you aren't getting in no matter how much you kick and scream and claim you are entitled to experience all the content because you bought the game and are paying monthly! (will be interesting to see who is actually around after the first month...)