Well, "every" parent may believe it but we actually are socially conservative around here. Look up the voting stats for my area (south central Washington State). As I suggested, the elementary school teachers and administration are just like the parents around here. As you go up through the grades there would be a little more liberalism creep in.
I can guarantee there are ways in which every day your children in public school are being conditioned to think of the government as their co-parent. This will build and build upon itself over time.
We presently are not allowed to talk to the insurance company about our 16-year-old’s medical bills charged to OUR policy. Since he is 16, under federal law, he has a right to privacy from his parents in this case. So when they call to ask questions about what appointments have been set, they do not allow us to answer those questions. They insist on talking to him.
The schools bring kids up to instinctively feel that there are many situations where they do not have to and should not seek the advice or counsel of their parents, or even inform them of various things. It is very subtle.
And, yes, it can be countered somewhat by how parents teach their children at home. But honestly if the school teaches kids from an early age that it’s best to talk to the school nurse about x, and they needn’t bother with telling mom or dad about it, it just doesn’t occur to them that there’s something wrong with that picture.