Seriously, much as I like English, it's largely the whim of circumstance that it's the dominant language of USA. Depending on the fickle finger of fate, we could easily have been speaking Spanish, French, Dutch, or even Portuguese. And if anybody has a claim to righteous indignation on the subject, well it ain't those of us with ancestry east of the Atlantic anyway.
At the same time, there are times when I understand the urge. D.C. is one of the most cosmopolitan cities in the world, and so just a drive down a quaint suburban street will confront you with an endless array of storefronts and church marquees in Spanish, Korean, Vietnamese, Russian, Chinese, Indian, Arabic, etc., etc. Just like sometimes you want to go where everybody knows your name, sometimes you want to go where everybody speaks your language.
The same thing is just as true of culture and subculture, really, and I suspect the fixation on language is just a subset of this. Race, ethnic background, whatever, are all pretty irrelevant when you're "on the same page" linguistically and culturally. I had a black friend in high school (Arthur) who was more or less a pariah among the other blacks as far as I could see, but with whom I got along beautifully because he was an artsy nerd like myself. Ditto my Vietnamese friend Khoa, whose thick accent didn't make him any friends among the social elite, but with whom I got along with like gangbusters because we had similar senses of humor.
That's the main appeal of conventions for me, I think. Making a little money is nice, travel is a good thing, meeting various celebrities is cool, and doing a little shopping for geeky stuff is always fun. But really the appeal is to be able to go somewhere where people really do "speak my language," not just literally but also metaphorically. I once said to susandeer that the real point of a convention was to spend three-to-five days surrounded entirely by cool, fun, interesting people. Heck, even the most dreadful fanboy and I have a lot more in common than I do with half of my co-workers.
That said, I also can't imagine going around with a bumper sticker on my car that said, "Boring people suck. Speak Klingon!" or whatever. Besides being terribly rude, it's pointless -- I'm not going to convince anybody to become a geek who isn't one already. Just like Mister "This is America" isn't going to win over any hearts and minds, he just makes himself look like a jerk. I suppose, having had his little rant and waved his little flag, he might feel better. But that comes at a pretty high price, if you ask me.