I usually think of Matt Yglesias as highly overrated but he simply nails this one:
I’m fascinated by how common [Mark Steyn's whiny] depiction of American education is considering that it’s 100 percent false. No doubt there are bad history teachers and bad history classes in the United States, but anyone who’s vaguely in contact with reality can tell you that U.S. history is very much taught as a heroic national narrative. But since contemporary American conservatism is eye-deep in racism, Steyn can’t quite seem to grasp that teaching people about Rosa Parks and so forth is part of the heroic narrative of the victory of American ideals over the worst impulses of human nature. Similarly, the much-bemoaned-by-rightwingers greater attention given in recent decades to the contributions of women and ethnic minority groups is about trying to expand the circle of people who feel invested in the national narrative.