Human cognitive illusions are powerful. It is by no means guaranteed that any number of human brains attempting to grapple with a problem will arrive at a correct answer. Democratic and scientific processes of sharing information and authority help a great deal, but one commonality all human beings have is fallibility, and crowd-sourcing more fallible brains doesn't eliminate that instrumental problem in truth-seeking.

(That said, I do appreciate the disagreement I often receive from other participants on HN as a reality check on my own thinking.)