Right! But smoke with smoke, and spark with spark... I don't go into the conversion mode in response to the aside about church, but I *do* make asides about atheism.
I just want them to realize that it is an existing world view, rather than something they've only heard of but couldn't happen here. It's kind of like coming out of the closet, I imagine. With the chance that the parents, in fear and loathing, instantly cancel any possibility of playdates with my kids.