Half the point of going to school is socialisation, learning to interact, not simply diffusing the parents' biases and ignorances.
A lot of people think they are qualified to educate their children, but unfortunately, 95% of them are unqualified (that is to say, incompetent). At the same time, being in Japanese schools, and having gone to a public school myself, it was the luck of the draw. It all ends up a lottery of having had competent teachers.
Sorry that I'm adding nothing to the actual question.