The issue is that influence matters more than the average or median in themselves - although oversimplified and "catchy" ideas tend to be favored more. This doesn't neccessarily mean dumb is favored per se - promoting say eating criminals would be an overwhelmingly unpopular idea even without constitutional limits.

They aren't guaranteed to be smart or just (sadly there probably isn't anything which qualifies) but they are are stable in a "not likely to piss off everyone into an insurrection" way.