Dan DiMaggio explains all.

All this reminds me of Professor Joel Spring's work [pdf] on schooling, not least his Education and the Rise of the Corporate State (Boston: Beacon Press, 1972), A Primer of Libertarian Education (New York: Free Life Editions; Montreal: Black Rose Books, 1975) and The Sorting Machine: National educational policy since 1945 (New York: McKay, 1976; updated edition, 1988), books that today's critics of state schooling would do well to read.