Sasha Volokh has a post up about compelled speech and raises a point I've made before: it's impossible for any useful education system to be ideologically neutral (see that post for my specific concrete example).
Mr. Volokh summarizes the problem with public education very succinctly:
(a) The government shouldn't set up a system that rewards people for subscribing to one ideology over another, violating their religious or other deeply held beliefs, etc. (b) Unfortunately, any drama/literature/etc. program worth its salt will violate someone's deeply held beliefs. (c) Therefore, because the government would only be permitted to offer an awful, useless, watered-down program, it should leave it to the private sector.Not only that, but public education is expensive and ineffective.