In light of all this self-reinforcing ignorance, Brennan argues that democratic elections are a crazy way to make important decisions. No one would submit to an operation by a doctor who refused scientific evidence, or think a jury of fact-resistant partisans had any business sending them to jail. But by ultimately entrusting life-and-death decisions to our fellow citizens, we are launching wars, sustaining mass incarceration, and punishing people harshly for marijuana use and (until recently) same-sex relationships on the basis of ignorance and prejudice.

Highly-educated guy overestimates the value of his education.

Ignorance is in part proportional to a current need to understand. You'll find that politically ignorant people often know quite a bit about some things, and their beliefs are largely structured by those things they know something about. People learn quickly when the need to, and excluding anyone from advancing their interests at any future time misses a fundamental quality of democracy.

That said, I tend to think that voluntary voting might be a good thing for this reason.