I think it is simply that, over time, liberal beliefs erode intellectual capacity and in a relatively short while, liberal people end up as little more than arc-reflex machines, always looking for ways to make reality fit their liberal delusions.
Take Roger Ebert, for example, the man cannot be as old as he is and as successful as he's been and yet be as stupid as he appears. Liberal thinking is the link between Ebert, Nads, and the rest of the Reality Challenged.