This has implications for a child's understanding of economics, foreign policy, American history and the size and purpose of government, in addition to what once were known as "traditional values." It is about reflecting the worldview of the teachers unions, who are in the pocket of the Democratic Party. In other words, the Left uses public schools to produce the next generation of Democrats.
The tragedy is that too many conservative Christian, Republican parents who want their children to have a different worldview - their own - willingly participate in the destruction of their children's minds by turning them over to a way of thinking that is antithetical to their beliefs. Parents who worship at conservative churches on Sunday willingly send their children to schools five days a week where what they are taught undermines what they learned in church and at home. They would never think of taking their kids to a church that teaches doctrines opposed to their beliefs, but they don't give a second thought to doing the same thing by sending them to government schools. It makes no sense.
Some parents don't have much of a choice: Their (tax) money is being used to support the public schools, and there's not enough paycheck left over for private school tuition. Which is why these parents need vouchers or tax credits.