Our dd doesn't attend the religious classes but she does here the kids talking about it after the classes. She has a logical scientific mind and questions how god could make clouds when it's precipitation (her words to us) and rain and sun that makes rainbows, we explain that different people have different beliefs and that's ok and it's up to her what she chooses to believe in. We talk openly about different religions and would let her do the classes if all religions were covered but it's not the case at our school.