I don't think that is entirely typical. The ones I have seen, or heard of from friends, back in the hippie aftermath, California, and Europe, were more of a couples situation.

Have you ever stayed in the Chicago or Washington, D.C. YMCA? My impression: not visibly "traditional" "Christian", despite the name, 1960s or so. I just expected them to be a safe and reasonable-price place to stay. Earlier, I used to swim a lot at a more local YM"X"A, and then I was quite naive, didn't know/notice anything odd, although I remember this one guy self-consciously holding his tobacco pipe in a strange way, I thought. Maybe he was just uncomfortable about smoking?

Duroc:" Out of curiosity were you brought up in a pretty religious home?"

Yes. My conventional protestant freedom/principle sympaththies, Catholic-, Mormon-, and Jew- tolerant roots show, I guess, although now I claim to be agnostic.

(added)You always have your roots, even if you don't attend the sweat lodge, eh? :-)(/add)