@J
IANAL, or even American either, but I do live here... I have the impression that the constitution outlaws the establishment of religion in *public*, gov run workplaces and the like. Not in private ones. But as I said, I could be wrong. It's know to have happened... frequently.
On the other hand, there are other laws against discrimination and unfair dismissal or whatever the name mentioned, which is what the two guys are (rightfully, IMNSHO) working with.
The reason why they will lose because its discriminating against people of other faiths , and atheist.