[Fairfax]

I think the main problem for men is that nudity has become so much more sexualised over the past few decades.
Probably started around the end of the 1970's when both color TV and magazines became common place.
This meant women with there sexual bits hidden (mostly) were free to enjoy wearing skin tight garmets but men with there genitals protruding are still regarded as sort of nude and therefore sexualised.
Not the same as completely naked but certainly in a grey area that is discouraged.
An excemption exists for serious sporting activities (mainly swimming and cycling but also things like body building) and men who enjoy wearing skin tight garmets certainly take advantage of it.