Rationalism is a great idea. I mean, who doesn't want to be rational? But it often makes me disappointed, because rationalists commonly leave about 98,3 percent of all phenomena in the world outside rational thought.
Sexual modesty is one of those phenomena. People, rationalists included, practice modesty every day. People all over the world, as long as they aren't mainstream Westerners, talk about it. But in Western culture it is a somewhat taboo subject. We follow culturally formed, arbitrary modesty norms all the time. In spite of knowing that the norms differ highly between cultures and that they are thus entirely possible to negotiate with, few Western people make any attempt at doing so.
As far as I have seen, rationalists are no exception. That is wrong, I think. If we are to be rational, we should be rational over everything.
Our cousin the chimpanzee is not known for its great levels of modesty. When a male chimpanzee wants to have sex with a female, he simply shows her his erection (like a dick-pic for creatures who lack cameras). When a young female has sex with the alpha male she commonly vocalizes at climax. 1