Sure, but most of them are probably "culturally Christain" in a broad sense. For example, most of them would be able to explain in broad terms the religious sig

Sure, but most of them are probably "culturally Christain" in a broad sense. For example, most of them would be able to explain in broad terms the religious significance of the festival and feel comfortable following a number of religiously tinged Christmas traditions. It's worth bearing in mind that most religious festivals are not celebrated only by devout followers of the relevant religion.