When the government established its school system -- gradually, state by state in the 1800s -- its goal was to provide a minimum of academic learning while training children to be obedient to authority and predictable as consumers in a "mass market." Government wanted soldiers and factory workers. It also wanted a market for the products of the industrial revolution and political support from the masses for its policies and candidates. The school system provided both.
Nothing has changed, except that academics have been dumbed down while the indoctrination has expanded by new techniques of psychology and new goals of social engineering.
The schools now believe they can get away with almost any outrage, because, as we discover every year at budget time, they have the votes. The people who work in real world jobs -- producing goods and services that society needs and wants -- earn the money and produce wealth. They are called the Makers. Those who work inside the government system produce nothing, and (together with their families) are called the Takers. The number of Takers has now reached critical mass whereby they can vote for whatever they want, and get it.
The big trick was that, long ago, the public were convinced that it was our duty to pay for this system of education.
"Private enterprise maintains and expands itself by continually offering people things they want. Government maintains and expands itself by depriving people of things they want, by means of seizing their goods (taxation) and preventing them from trading and living as they choose (regulation). Thus, private enterprise continually increases the prosperity and well-being of its customers, while government continually decreases the prosperity and well-being of its citizens." *
*from the book, The Market for Liberty, by Morris and Linda Tannehill