I just love Silvertip's "highwaysign" picture. Cool guy, lots of courage!!
But bear in mind that even in relatively undeveloped tribal societies, both men and women hide their genitals in public, and often even their anuses. It seems to be hardwired into us (if I may use what may seem an inappropriate term under the circumstances!!). Maybe it's just for protection, but I think it's for modesty.
Having said that, I see no shame in being naked in appropriate places, which includes in the home (yes, even in the presence of kids, it's perfectly healthy for them to see the human body unadorned), in the presence of close friends, and on nude beaches. I'm of a somewhat older generation where guys were perfectly relaxed about being seen naked in the locker room, by their room-mates, and an opportunity to go skinny-dipping was treated as a fun event!! The YMCA and even many colleges had a standard "no swimming costume" policy in their men-only swimming pools. Yes, this was often a cause of embarrassment for some of the more bashful guys who were insecure about their bodies, but for most of us it was perfectly routine and normal. I'm sure most of us sometimes looked the other guys over, making comparisons about the bodies in general, perhaps feeling envy, or perhaps pride, and even wondering who among them were perhaps gay. Isn't that what being human is about? But mostly it was just an everyday type of event.
I was never in the army, but in the barracks open showers used to be standard.
I regularly hang around the house and private areas of the garden naked and swim nude whenever I get the opportunity!! I've been to quite a few mixed-sex nude beaches and really enjoyed the freedom.