Why must education include values and morals? Why not fact, figures and (sometimes) method? Whether automechanics, pottery, mathematics, physics, or whatever, these can all be taught from either a fact basis (here are the facts as we seem to know them) or from a historical basis (here's how we've come to the current framework).

Maybe literature and all of the soft sciences come with some form of innate bias to the teaching of them, but this can be made explicitly and with the offer of the alternative interpretation.

You might claim that any class on, say, astronomy should include a "flat earth" view but I think that there are reasons why the curriculum of Byzantium -- thaumaturgy whatever -- is not taught.

This is not to argue for public education, just to say yout hypothesis is hard to prove to be as absolute as you make it seem.
 

I am talking about the content of education, and more on that in a second. But I am also talking about the form. The medium is a message.

What does one learn in elementary school? To obey adults not your parents; to obey authority. You learn that smarter kids are more valued than dumber kids. You learn that learning is a specific activity, that is done in a particular way, in a particular building, with professionals. (If you are homeschooled, you may learn different things; but this is my point. You are learning things from the form.)

You learn that learning is valued. Learning good. You learn that some things -- math, language, art, music have great value; they are subjects of much teaching. Other things -- playing outside, chatting with other kids -- have lesser value; they are permitted at least sometimes, but not taught. Other things have even less value: they are not taught and no time is made for them. Playing computer games. And finally there are things not permitted: hitting others, use of politically incorrect language, drawing pictures of guns. These things are of the lowest value, negative value, and will be punished.

Now, on the content, you're right: literature (for example) comes with innate bias. Let us assume that we will teach English. Well, you do this the students will have to read something, be it only cereal boxes. And they cannot read everything. Hence, the teacher is imposing judgments of what is good, and worth reading, and what isn't.

In the real world of socialist schooling, these judgments will be far from trivial things. Hence kids will be reading "Heather has two mommies", or not, depending on the political correctness of the local politics. They'll be getting drug education, as we did, that lies to them. Or not; though I don't think the latter is very likely.

Even in hard science, there is meta content. Do I want flat-earth "theory" taught to my kid? No, of course not. But I will concede that all of science rests on some unprovable things. Induction, for example. Logic. Reason. Theories about our innate ability to apprehend the world. Clearly I think these are good things, and obvious, but I can't prove that to a doubter. Thus, the teaching of them ultimately is religious.

It may be hard to see that, until you try to actually imagine the way a super-religious person thinks. How do they manage to accommodate a literal Bible and anything like what I regard as a reasonable basic worldview? I don't get it. But I can see that there must be some real differences, and they must be somewhere down pretty close to the bottom. I can see that they might be very unhappy with their child being taught any science at all, or perhaps they have a variant where God's will, and God's ability to transcend physical law, is stressed from the outset.