What world do you live in.. lol
I don't know if it's just North American countries, but besides public schools, all the other schools have a seperate period time for the subject "religion". I used to go to a Catholic school during my elementary schools, and like every other period, we had religion for 45 minutes every single day of the year. We also had to pray before we start our class, before we eat our lunch, and before we leave the school. We also had like Christian assemblies and mass and stuff like that, so yeah, there's already schools that teach religion..