You are either not understanding, or not wanting to understand, the difference between the score on a reliable IQ test and the SAT scores of just the LWers who took a SAT. Obviously, an IQ test is a much better indicator, also SAT is only available for people in the US. Also, the responses I'm getting are already very different from the survey.

JCTI's reliability is verifiable from the link, even though the other test's is not.

sitting around talking about how smart we are doesn't send signals to onlookers that I think are in the best interests of LessWrong.

Investigating a phenomena is what we are about. I don't see a logically valid reason to not investigate this one, especially if previous data suggests an abnormally high level. This holds true even if the concept of IQ is invalid, as long as it is measurable.