One commenter, CRM-114, asks
BTW, what if they get a Jew or Muslim in the geometry class? Do they get alternative instruction fitting their religion?
which leads to another commenter, chaos_engineer, writing the greatest comment in the history of the internet.
Of course. Christians would be taught real geometry, with the Euclidean version of the parallel postulate.
People who practice flawed religions would naturally be more comfortable studying flawed, non-Euclidean geometries. Jews could learn Riemann’s version of the parallel postulate, Muslims could learn Lobachevksy’s, and atheists could learn H. P. Lovecraft’s.