Time in a school day, and space on a page, are limited. Choices must be made in how to fill that day or that page in a textbook. In making those choices some topics will be stressed, others minimized, and some ignored completely. Those choices are NOT NOT NOT politically, culturally, or religiously neutral in content or consequences!
FUNDAMENTALLY, government schools violate the First Amendment and freedom of conscience. They are an abomination!
Solution: Begin the process of privatizing K-12 education. Shut down the government schools. Move toward complete separation of school and state.
And what authority does the federal government have to dictate to the states what their school curriculum should be?