I don't see any harm in religious ed or ethics class. In addition, I believe if you attend private school and know what the expectations are ahead of time, it should not be a shock. However, no one should be *forced* to pray (as in get detention if they don't).
In essence, it gets to the heart of the question: What is prayer, and what is it for? In my opinion, prayer can be one of two things:
1. Some kind of community get-together, where you find comradeship among other people who share your belief. You share experience, you share ideas, and you share your communal whatever you want to call it.
2. You go deep within and meditate, calm your mind, and evaluate where you are going. You take a break from fast-paced life and really see if where you are going jives with your inner self.
Both are valuable and purposeful for different people, but neither should be forced because they simply cannot be. Either you want to engage in that kind of behavior because it is meaningful to you, or you do not.