As one data point, I'm allergic to almost every aspect of the modern American nerd culture, but I don't find it problematic here because I simply tune out any manifestations of it. However, I have an unusual level of ability and inclination to filter out the elements I dislike and concentrate on the interesting stuff whenever I find some venue offering original perspective and insight. I'm sure lots of people find such things more actively repulsive.
Unfortunately, all these data points have been already filtered. Learning that some non-cultural-nerds aren't scared away by the nerdisms here is good, and thank you, but I wish I saw way to coax a more meaningful statistic out of them. "100% of non-nerds who still post on Less Wrong haven't been discouraged away from posting on Less Wrong", fine, but for each one of you are there 0.01 or 100 others who didn't stick around?
I'm reminded of a comment here about "borrowing offense": you can't try to single-handedly anticipate and elimina...
Less Wrong is as a community extremely nerdy. That's true for almost any definition of "nerd" that captures anyone's intuition for the word. However, to a large extent, many aspects of nerdiness are not connected to rationality at all, even though nerdiness may be associated with more rationality in some limited aspects. For example, fantasy literature is probably not in any deep way connected to either intelligent or rational thinking except for historical reasons.
Yet LW is full of references to science fiction, fantasy literature, anime and D&D. In one recent example, a post started with an only marginally connected tidbit from Heinlein. Moreover, substantial subthreads have arisen bashing aspects of other subcultures. For example, see this subthread where multiple users discuss how spectator sports are "banal" and "pointless". I suspect that this attitude may be turning away not only non-nerds but even the somewhat nerdy who enjoy watching sports, and see it has harmless tribalist fun, not very different than friends arguing over whether Star Wars or Star Trek is superior which has about the same degree of actual value here.
There's a related issue which is a serious point about rationality and human cognition: Our hobbies are to a large extent functions of our specific upbringings and surrounding culture. That some people prefer one form of fantastic escapism involving imaginary spaceships isn't at some level very different than the escapism of watching some people throw and catch objects. Looking down on other people because of these sorts of preferences is unhelpful tribalism. It might feel good, and it might be fun, but it isn't helpful.