A Brief Note on Autodidacts
Everybody is an autodidact (at least after the first few grades of elementary school).
Students teach themselves. At most, the teacher saves a little time and provides occasionally-useful advice on what topics might be important.
This explains why Transfer of Learning (one of those topics that apparently require capitals) is so rarely observed. There is no good control group. Students who didn't take course X aren't a good control group because, if needed, they can find out the same things themselves.
There are two important things that are usually done in school. 1) Finding out if the students actually learned anything. 2) Correcting common mistakes. I suspect the left-wing bias among schoolteachers is more a matter of not correcting left-wing bulshytt than in proclaiming left-wing ideas.