To teach use of a non-free program is to implant dependence on its owner, which contradicts the social mission of the school.
Bertrand Russell's The Impact of Science on Society (1952) should probably be given another read:
Fichte laid it down that, education should aim at destroying free will, so that, after pupils have left school, they shall be incapable, throughout the rest of their lives, of thinking or acting otherwise than as their schoolmasters would have wished [...] to produce the sort of character and the sort of beliefs that the authorities consider desirable, and any serious criticism of the powers that be will become psychologically impossible. Even if all are miserable, all will believe themselves happy, because the government will tell them that they are so.
Now consider when the http://en.wikipedia.org/wiki/Bilderberg_Group met for the first time (1954) and who gets to attend...
WARNING TO ALL PERSONNEL: Firings will continue until morale improves.