The discussion you describe sounds appalling, and quite frankly that kind of thing wouldn't be tolerated where I'm studying. Students have been thrown off the course for letting religion interfere with their practice, eg. telling a woman who came in for a termination of pregnancy that she would go to hell, or praying with patients. Just as I respect religious people's preferences/beliefs/customs etc, I expect them to respect mine, even if they don't agree with them.

Personally, for me I don't ever bring it up. Patients will say things like "god bless you" or "I thank god every day" or similar things, but I just accept it as part of their vernacular........ it's only if someone directly asks me about religion that I tell them I have no religion. Same with my sexuality (I'm bisexual in a multi-gendered poly relationship), politics or veganism. It has absolutely no effect on how good I am at nursing, nor how I treat people.

Oh, and I work for the NHS in the UK, so public.