How do you figure? The whole idea of private schools is to get the financially able, the education of their children, they want, without the little tikes having to sit in the same classrooms as the poor liberal public school ethnic populations. This is America. If you have the cash, you can set up a school to teach your kids any version of reality to any skill level of normal academic achievement, enforcing your values, up until you send them to a top flight private university.
But, you can't get what you want, if too stupid to check out the private school you are hiring before you plunk down your money and have your kid dropped off. Of course they are like any other private business, marketing themselves as they please and having their own company/corporate culture and method of doing business. If you think you will send your kid there, and then go in and change them to your standards, you got to be nuts or brain dead stupid. It is not like public school, with a school board of elected members and taxes paid. This a private company. They can tell you to take your brat and hit the road, and if you are too loud, and phrase your complaints wrong, they (like any other school) can report your ass to the police, the Feds or anybody of their choosing. If they think you could be a danger, the authorities treat their report the same or possibly better than any public school and will investigate.