It's a convenience sample!

LW would have roughly 25 times the baseline AS rate.

The Less Wrong mean average AQ test score was 27

Only about 1 in 10 people on Less Wrong are "normal" in terms of the empathizing/systematizing scale.

This is grossly overstated, because the survey respondents are in no way known to be representative of LessWrong. In fact, I would suspect a very strong selection bias. Before you can go saying anything about the LessWrong community, you need some response statistics. How many people were offered the survey? (You could get this from the server logs. Your survey wasn't promoted and was only up for a day or so, an exposure that already subsets its audience from "LessWrong") How many of the people who saw the survey decided to fill it out? How do the people who filled out the survey differ from the people who did not fill out the survey? I doubt the answers to any of these questions would be satisfying unless you started with a random sample, then individually and privately invited each of the sampled people to participate. Even then, the response bias might be bad enough to preclude any conclusions about LessWrong.