Simple. Right-wingers tend to occupy the middle of the intelligence spectrum while left-wingers occupy the lowest and the highest (at least Democratic voters as a whole; many of the less intelligent Democrats don't understand liberal vs. conservative). However, the lower-middle end, in which many of these comments are from, is generally more conservative (note that Atlas, both left and right, is at the upper end of intelligence).
You're mixing up intelligence and education. They are far from the same.
A common fallacy of the snobs.
Anyway, what Bacon King and Gully said. I also think that right-wing morons feel less inhibited about posting things like, "Barack Obama is a Communist who wants to destroy America!" on "mainstream" sites than left-wing morons, whose equivalent posts would include, "America deserves to be destroyed by Communists", etc.
Finally, I question whether there is an equal number of morons on the Left and Right in America. Somehow, I suspect that the Right has a disproportionate share...
