Chuck:

You write: "Since all that separates al-Qaeda from the Nazis is the means ... one wonders why a certain amount of cognitive dissonance wouldn’t kick in after a liberal enjoyed screening “Basterds.” "

Have you not considered this depressing possibility: there will be no conitive dissonance for the simple reason that some people see al-Qaeda as the Basterds and the U.S. as the Nazis?

Insane? Sure, but the insane don't dissonate much.