Interesting thought, because I'll be attending PAX in Seattle next week; one of only two times I'll claim having had the ability to dip my foot in the Pacific Ocean, but my point is that I'll be among thousands of people who gather for the sole reason to be proud that they're "a gamer".
Further criticism could be leveled at the term simply because of the fact that being "a gamer" still says very little about what you are, and simply going to PAX this past March proved that to me like nothing other. Are you a sports games fan? Do you enjoy FPS? JRPG? WRPG? etc. etc. Are you someone who jumps at every new gaming system and technology, or do you still hunker down with the NES on occasion to play some Dr. Mario? Hell, what about tabletop games, board games, and P&P RPG?
This reminds me of my last girlfriend, to be honest. She is "a gamer", too, and it was one of the bases on why we got together, yet in the end we found very little common ground on what kind of games we enjoyed. I play a veritable hodgepodge of stuff, and usually the more obscure and "arty" the better for me, but I still imagined I played enough of a range that we could find something we enjoyed together. Welllll guess what: she enjoys WRPGs, simulations (like THE SIMS *thunderclap* and Tropico), and D&D, and very little else. All three of those genres I was very loosely attached to, so sadly, there was a nice little roadblock in our relationship. Plenty of other reasons why we didn't work out, of course, but a lack of being able to play together often did not help.
So it always leads me to caution when I go to these large conventions about the kind of genres these people enjoy, and wondering if being "a gamer" is really all we need to define ourselves as having camaraderie. We may be shooting ourselves in the foot with such a collective label, tearing ourselves apart from the inside, and we may not even need people on "the outside" to bring us down.
