Regardless lets start with the very premise of a public school. The very idea of a state run school system should fill anyone with grave concerns. Those with a passing knowledge of the rise of socialist and communist states should be even more concerned. Knowing further that those who molded the American modern educational system were socialists should only increase those concerns yet again.
Given that the state runs the educational system, with no constitutionally enumerated power to do so, that it was designed by socialists that published their concept of spreading socialism by incrementalism starting with indoctrinating the youth, that the tax dollars spent on education keeps going up wildly while the standards of education are plummeting, that the leadership of the teachers unions have been overtly progressive for decades, that teachers plead poverty while their salaries and pensions are driving states to bankruptcy, your biggest concern is that a teacher might quote the bible or lead a prayer session? Really?!
You need to examine your axioms because your reasoning gravely flawed.
Teaching morality is a little different from having prayer meetings. I have no problem with Christmas plays and the like in public schools. What I do have a problem is with public school teachers saying or leading students in prayers in the classroom. If you think the proper role of ps teachers is to lead students in prayer, then you better study what the constitution really means. If students want to have prayer meetings with teachers not on school time, that’s one thing. And I don’t give a fig how much or where it was done in the past. It has no place in a public school classroom.