This is one of those "important research with unbelievably flawed methods" sort of situations. Psych research before IRBs was crazy.

Nowadays there's a lot of FUTON bias in research. There's so much power in just hitting the streets or reaching out to your circle.

For the most part, you care the most about your circle, so if that isn't representative of the whole of society, it sounds like somebody else's problem. Who said all research needed to be perfect.