Earlier, I posted saying that nudity in the saunas is normal, which I have known since the late '80s without ever setting foot in one again. In fact, I remember something that reinforced this to me: ~8-10 years ago, there was a big "MRSA at gyms" awareness push/scare and I read that sauna owners required all to at least sit on a towel.
Now, if that doesn't seal the deal, there's a 10 year old Family Guy episode where Chris takes his towel off in the sauna causing his father to get penis-envy.
Do you sit on the toilet in public restrooms? Same thing.
The cootie fear mongering in this thread is amazing.
No, it's not the same thing. A toilet seat changes temps and dries off which, for infectious virii and bacteria, is a big enough change from their ideal environment (the human body) to kill the vast majority. A sauna stays warm and humid.