No one is advocating that we throw in sports and celebrity references.
I am. Why shouldn't we?
Admittedly, almost no one who is attracted by discussion of sports and celebrity meets community standards for rationality, most of us would find it difficult to include such references, and it would increase the willpower required to read LW for some people, but these do not mean that we are currently at the optimum level of sport and celebrity references. Given that we're all a bunch of nerds with a huge grudge against mainstream tastes, it seems quite likely that we're under investing in sports/celebrity references-I'm quite certain that there are concepts that we discuss which would benefit from comparison to sports/celebrities. Also, though we won't attract people to LW via sports/celebrity references, that doesn't mean that we couldn't raise the sanity waterline outside of LW by creating rationality related material in language that appeals to non-nerds.
it seems quite likely that we're under investing in sports/celebrity references-I'm quite certain that there are concepts that we discuss which would benefit from comparison to sports/celebrities.
But to grasp those concepts we'd need to actually learn a lot of mostly-useless, occasionally-relevant facts.
When an LW post says Gandalf should have brought Frodo to Rivendell as soon as he suspected he had the One Ring, the whole point of using that example is that readers understand it. If the post had to explain who Gandalf was, there would be no benefit ...
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.