When I lived in Lippstadt I had great neighbors. I lived in Lipperode, a village that belonged to Lippstadt. The fascinating single mom next door, the heating oil guy and his wife across the street, the lovely couple in their 50s on the other side, and next to them, kitty-corner from us, was Horst.
Horst had taken early retirement and was quite involved locally. He volunteered a lot, one of his positions being President of the village board for the protestant church. A Calvanistic church, to be exact. It was unusual for a village to have a Calvanistic church, but like many other German villages, it also had a Catholic church. Horst made sure to point out to me that the Catholics and the Protestants in Lipperode got along, they always have, and he was sure they would in the future, too.
Then Horst looked at me and said
Sind Sie katholisch oder evangelisch?
My cheeks flamed and my eyes gaped at his question. I hadn't learned enough German yet to know how to say "None of your business!" I was offended by his question. No one had ever asked me that before and according to my Midwestern American upbringing, it was a question you just didn't ask.
I mumbled something about having grown up American Lutheran, and that was surely something different, and suddenly he wasn't interested any more.
In dealings with others, I realized it was the same kind of questioning as "Have you gained weight"? He just wanted to know. And when he knew, that was it. It was a simple Feststellung.
In addition, religion isn't as much of a controversial topic in Germany as it is in the US (unless we're talking about building a mosque in downtown Köln, and then things can get heated). German's don't shy away from discussing politics and religion to the extent that Americans do, although any deep or lengthy discussion is certainly reserved for more personal relationships.