Here's a nice piece on Capitalism Magazine's site on multiculturalism and its effect on education. I experience this at least once a week when speaking with my kids about what they learned.
A quote to whet the appetite:
What these textbooks reveal is a concerted effort to portray the most backward, impoverished and murderous cultures as advanced, prosperous and life-enhancing. Multiculturalism's goal is not to teach about other cultures, but to promote--by means of distortions and half-truths--the notion that non-Western cultures are as good as, if not better than, Western culture. Far from "broadening" the curriculum, what multiculturalism seeks is to diminish the value of Western culture in the minds of students. But, given all the facts, the objective superiority of Western culture is apparent, so multiculturalists must artificially elevate other cultures and depreciate the West.
If students were to learn the truth of the hardscrabble life of primitive farming in, say, India, they would recognize that subsistence living is far inferior to life on any mechanized farm in Kansas, which demands so little manpower, yet yields so much. An informed, rational student would not swallow the "politically correct" conclusions he is fed by multiculturalism. If he were given the actual facts, he could recognize that where men are politically free, as in the West, they can prosper economically; that science and technology are superior to superstition; that man's life is far longer, happier and safer in the West today than in any other culture in history.
The ideals, achievements and history of Western culture in general--and of America in particular--are therefore purposely given short-shrift by multiculturalism. That the Industrial Revolution and the Information Age were born and flourished in Western nations; that the preponderance of Nobel prizes in science have been awarded to people in the West--such facts, if they are noted, are passed over with little elaboration.
Again, I experience this weekly (most weeks, anyways), and so have my own evidence to back this up. I spend at least a few hours undoing some of this stuff. It's worse at public schools, but private schools certainly aren't perfect.