but seems to have no bearing on a Church on THEIR PRIVATE property.....
Indeed! The pretext for suppressing a Christian's exercise of their 1st Amendment rights in public schools settings was the assertion that John Q Public wouldn't be able to distinguish between Congress passing laws and School boards creating policies. This is a classic example of using twisted logic to stand the 1st Amendment on its head. Christian students had, for over two centuries, practiced their religion in public schools, wrote school papers about their Faith and experiences, prayed over their meals, and even at school events. For two centuries politicians and citizens understood what the 2st Amendment said and meant.
Suddenly, the School Boards had to establish regulations forbidding that which had been a Constitutional right for centuries, and really still is, doing in effect what Congress cannot do, pass laws prohibiting the free exercise of religion or establishing a religion. It was a clever back-door attack by the ACLU, and the tactic has been repeated several times on other political topics, including the 2nd Amendment. It is rare that the ACLU will support a "Founding Fathers" position on a question concerning the Constitution. They are a bunch of clever lawyers but they aren't smart enough to see that they are cutting their own throats.