He is a smug asshole who thinks Americans are stupid because we used our post-WWII wealth to do things -gasp- like build suburbs and freeway systems. He generally thinks we ought to be ashamed of this, and this is typical of liberal thinking to mock personal freedom and choices.
BTW, I am a left-leaning Democrat and am appalled by the Bush administration in every respect. But I find a lot of talking-head liberals to be ingratiating because of how they argue points and conduct themselves. I chose to bash Kunstler because his smug, egomaniacal style is probably the worst example of these types.
So what if he's a bright guy and a lot smarter than me? He's still an asshole.