Seems to me that it makes fun of both American liberals and conservatives, but mainly from a liberal's angle of wickedly satirical humour about the conservative viewpoint OF liberals. Bill must have read it with only one eye open or something, and he has totally missed the point.

It is affectionate joshing BY liberals about extreme stereotypes of liberals, joshing done from a liberal perspective. It pokes fun at the utterly skewed and silly view of "liberals" that prevails in conservative America. It also is affectionate joshing at we Canadians...a bit overwhelmed at the sudden flood of Amos-like latte drinkers and Art Majors from Boston into the sleepy environs of the Great White North....eh? ;-) Canada is liberal. Trust me. We're very liberal. We even like socialism here, and the only reason we're in Afghanistan is that our present prime minister is really an android made by the Rand Corporation and he does whatever the Pentagon tells him to.