When that's not the context, we're usually talking about issues relevant to the general population, and the pitfalls of using LW data for that are obvious.

I don't think we only care about the general population. We care about the people with whom we are interacting on a daily basis. We have a bunch of people in this community who want spend time with rational friends instead of spending time with an average member of society.

Even if we are not intending with rational people we are still unlikely to interact with the average person. Most woman I meet, I meet during Salsa dancing. That activity selects for woman who are okay with strangers physically touching them during Salsa dancing.