“I have indeed two great measures at heart, without which no republic can maintain itself in strength: 1. That of general education, to enable every man to judge for himself what will secure or endanger his freedom. 2. To divide every county into hundreds, of such size that all the children of each will be within reach of a central school in it.”

Great vision (centralized, government run schooling for all children).

Comrade Anonymous, favoring secularism as the 'National Establishment of Religion' (denying freedom of religion and all other competing philosophies) seems to have missed Jefferson's desire while gloating on a miss-application thereof. As the Jews set up community synagogues and the Greeks small district colleges, Jefferson worked towards having schools within the government that most closly associated with individuals in any given area. As to a general education, enabling every man to judge for himself what will secure or endanger his freedom, Comrade's liberal and conservative ideologues have fairly efficiently eliminated that measure of the heart.

How can a socialist school system possibly teach freedom?

It benefits society as a whole when the population is educated. The better the education, the more prosperous and content the society is. Jefferson was a wise man to see this, unfortunately, globally speaking, US public education is rather pathetic.

In order to teach the doctrines of Liberty and Freedom, one must have access to that knowledge. Timing is everything. It is through
Prohairesis, and rigorous self-discipline, a foundation of essentialism to establish proper order and codification of knowledge and skill defined.
Secular perennialism and the indoctrination thereof, have brought about a demise, and the infiltration of corruption within the minds of our own children. I'm sure Thomas Jefferson would think highly of Epictetus. Prohairesis defines us from all other creatures.