Quoting David (bouncingcats@gmail.com):
Another data point: In 2007 I visited a relative in Tulsa, OK. The house was in a gated few streets with a shared swimming pool. It was summer and I went up alone for a dip and briefly small-talked with some strangers in the pool. After I explained my accent and where I was from and who I was staying with, it was the first thing they asked me. "So, what church are you with".
Weird, but I certainly believe you. Tulsa and the entire state of Oklahoma are a centre for backward badness of almost legendary proportions. The Oklahoma 'panhandle' area is said to be particularly hopeless. I mean, can you imagine even _caring_ about what church if any a stranger belongs to, let alone asking, uninvited? Seems unspeakably rude and quite wacky, to me -- but, as my father always said, 'Life is anthropology.'