I think learning about religions isnt a problem unless the teacher themselves shares there morals and beliefs about a specific religion.
Im Catholic, and everyone in my italian class is Catholic too..so since basically the majority of all italians are Catholic, she tought us one class about Catholicism in italy and etc, like we went online and picked our saint name, etc. It wasnt a problem to any of the kids in class because we were all catholic. But itd prolly bother the people in class that werent catholic or christian of some sort.
Other than Italian class, my freshman year in Social Science, aka history, we learned about all different types of religions.