On bubbles:

This is entirely the difference between the left and right. The left values cohesion of the masses, not progress or merit. The right values merit, not cohesion. Thus, the right willing engages in the battle of ideas to let the best rise, while the left censors anything that conflicts with their ideal vision.

Debate sites always start out dominated by the right, and usually end when enough leftists stop allowing debate in one form or another.