I think this mistrust of intellectuals is misplaced. Any kind of person, no matter education level, is susceptible this. Any person who is single-mindedly perusing his crazy view of the world and does not care of consequences is dangerous. Historically, intellectuals have had more means and knowledge to pursue their crazy ideas and I guess that is why they are more prominent.
It's certainly true that non-intellectual theories of the world can be very destructive if society places too much trust in them. That would be "superstition", I think. But it hasn't been the problem in the 20th or 21st century in most places.
Superstition does rack up its own respectable death toll though; a number of the other slaughterings that can't be credited to intellectualism of any kind can be credited to some large degree to superstitions, especially if you're willing to call racism a sort of superstition, which is at least debatable.
Good catch. I was trying to give a reason for this misattribution and not justify it.
But back to the larger point. It strikes me that intellectuals who have racked up the greatest kill-scores have done so because of their views in humanitarian fields (politics, philosophy, etc.) I am yet to see a genocide in the name of math or art. One exception I see is the misrepresentation of climate data to support global warming (if indeed that is true).