When they were first founded the students had an opportunity to learn to read and write, do simple math, introduction to sciences, learn some history, read books, move on to Latin and Greek even Hebrew in some schools.
And with local school boards being elected the subject matters can vary according to the desires of those boards as long as they prepare the students to pass the exit tests.
Today the better schools have a vastly expanded curriculum with advanced science and math, multi-year programs in half dozen or more languages, advanced courses in history, statistics etc.
Apparently you are unfamiliar with the realities of modern schooling preferring to put the ideological blinders on and swallow the anti-public school bilge regularly doled out here.
One of us certainly has blinders on. I have never just swallowed anything without looking into it. Right now you apparently agree with what is being taught in the schools where you live. That's good. Remember what I said when you no longer do.
Shalom.