re: "Movies, the nagging conscience of America"
Americans love blowtorching themselves, and it is easy to understand why.
Actually, this is not quite correct. The cultural elite love blowtorching America. It's not quite the same thing. I remember a hell of a lot of old films where America and its values were held high, too. Such films generally receive amused contempt from the critics.
Mention John Wayne or Jimmy Stewart in a university class on film criticism. See what you get.
Nothing endears a filmmaker to the high critics like crapping all over America and its values. Cannes is just the latest example.
A little more on this here.