I very weakly support making this an optional activity in public schools.
No matter your personal stance (I'm an atheist), it is clear that religion is very important to a huge percentage of the population. Knowing how religion motivates people and how people use religion as a means to achieve social and political realities is worth knowing about.
However, it is *very* easy to predict how this type of teaching is going to be put into practice. Many of the teachers are going to promote their religion and we all know which one. Even now, there are biology teachers who editorialize their opinions when covering evolution, how unbiased will the instructor be when covering non-christian religions?