I've observed the same talking to people here. Highly educated professionals (doctors, engineers, lawyers, scientists, etc.) seem to be over-represented on this site. This makes it very distinct from other websites which are, by their own admission, filled with NEETs and tranny welfare sponges. I tend to attribute this to a few factors:
1. Long form, encyclopedic posts tend to appeal to more educated people with longer attention spans.
2. High effort, well-research, well written posts tend to be rewarded, which aligns well with these people's values.
3. The subject of autistic weridos tends to attract other, albeit better adjusted, autistic weirdos; who themselves are over-represented in these fields.
4. These people tend to be more critical, even if only privately so.
5. The site's history of being attacked from all angles fosters a culture of self reliance, which again appeals to autists and people who have "made their own way."