Is it because they don't want to be thought of as abusing their children if they send them to these drone factories?
Is it because they don't want to face the harm the government schools may have done to them?
Is it because "it's always been done this way"? Because it hasn't, you know.
Government schools are funded through theft. You can't teach anyone to be a decent person with that kind of example. Government schools are the reproductive organ of The State. Sure, some people do well in them. Humans are incredibly adaptive. Sure, you can learn things in government schools.
But "Schooling" is NOT the same as education. They are completely unrelated, except that schooling teaches people to obey "authority" figures- thank goodness many never really learn that lesson.