Slate has an editorial that paints a grim picture of Bush and his intellect or lack thereof.
The piece sets out in detail the conditions that formed Bush's anti-intellectualism and how it has infected his life ever since. Unfortunately, if what the author says is true, then Bush has opted for ignorance.
But then, ignorance is a choice. People choose to forego educating themselves and thus choose ignorance. Some do it because they are lazy, others, like Bush, do it because they adopt an ideology that provides them with certainty. Bush began this odyssey into moron-land by becoming an evangelical. This inevitably led to ideology, since he was politically inclined.
Stupidity could be excused because stupid can't help it. Bush doesn't lack for ability because his parents and family exude ability, so stupid isn't his problem.
The damning aspect to this boils down to choosing to be an idiot.
We've all paid the consequences for his personal life choices.