The mindless postmodern culture to which I think you are alluding is not just America's - all us capitalist countries have had a hand in it, and contributed to the bland global culture which is imposing a trashy universality throughout the world.
Modern British polititians have since the '50's been imposing a 'multicultural' society on its citizens, no doubt fuelled by guilt and self - loathing from our colonial past. But they should consider this: Their ancestors may well have exploited India, the Irish and Black Africans, but at that time, my ancestors and most other Brit's ancestors didn't - they were working as virtual slaves in mills, on farms, if unemployed sent to the workhouse, and their children sent to be chimney sweeps apprentices, to die of soot inhalation before they were twenty. Why should we feel guilty?
Still, there is light at the end of the tunnel - the guilty descendents of the mill owners, colonists and slave traders can always escape the ghastly, terrorist - ridden monster of a social experiment they have produced and go and live somewhere else. We'll just stay here, and get bombed on the London underground.