Christian schools teach that Christianity is truth.
Catholic schools teach that Catholicism is truth.
Jewish schools teach that Judaism is truth.
Muslim schools teach that Islam is truth.
Government schools teach that Government is truth... :)
You can’t expect anything different. And I agree,
government schools are inherently anathema to our founding principals for this very reason.
And Parents, given the choice, try to select for their children that school which they believe teaches the Truth.
Except for the Government Schools. There you get whatever the Government decides to dish out.