I don't think that's true. For one, there are many publications about strict education and until relatively recently, it was the leading school of thought; we have movies featuring them, even praising them (Harry Potter for example - that was an example of a school lead as a benevolent dictatorship - that of course turned out bad later in the series). For two, people mostly don't read books about parenting but then they're parenting their kids somehow - how? Well, with whatever they picked up from their parents, TV, fiction books... Isn't it possible that it might be the same with teaching? I have some experience with working in education. Most of my former colleagues almost never think about the way they teach; you ask them why did they punish a student for disobedience (aka "he drank water even though I told him not to") and they say "because that's how it's done", you asked them why are they explaining something in that way and they don't know, they just do.