Why are old men always naked in gym locker rooms?

In the early 2000s Mrs. A and I joined the local YMCA. (No jokes.) There was a lounge off the men’s locker room with sofas, a recliner, tables and chairs and a big TV. Older men hung out there completely naked – not for sex (AFAICT) but just because they liked hanging out, watching TV and playing cards nude.

I wonder if that kind of behavior goes back to when there was a bathhouse every few blocks in old European immigrant neighborhoods.