Outside the US nudity is not so taboo. In my daughter's kindergarten (a nice private school in Southeast Asia) boys and girls share the same bathroom, with no private stalls, and no door on the entrance. Everyone sees everything -- passers-by included. Meanwhile, in the US, nudity is synonymous with sex, and good people have to worry about things like this.
I'm not saying that makes it sensible, but it does bring the American treatment of them closer together than they seem at first glance.
To my mind it merely identifies hypocrisy.
So in the progressions, when would the censors put the black boxes over the "naughty" bits? Would there be a difference in that for the man and the woman?
Much of the country was built and populated by puritans. State's rights and a lack of urbanization allowed tight-knit communities of like-minded people to keep anyone different away. This created a sort of moral echo chamber, that carried their views into modernity without ever being tempered via intellectual or moral challenge. And the US system of representation gives those rural communities quite a bit of power over national mores.
As for the rhetorical: it depends on context. It always depends on context. Nudity isn't necessarily less harmful.
Hiding violence and death away from children can be just as harmful as hiding nudity.
Whether honest non-exposure might be fine is beyond even an academic concern. It's overwhelmingly improbable that a child could be raised without being exposed to those things; short of willful sheltering.
I'm going to stretch my neck out (as it were) and say that most people in the world butcher their own meat and at least kill some of the meat they consume. Granted outside the wealthy regions this is rarely going to be large animals but still.
Many many peoples are exposed daily to the threat of major violence to themselves too.
I'll tentatively accept that the majority of humans don't directly witness brutal violence against other humans in their lives.
On the other hand, I hear that a really long time ago women always had really long dresses and the only skin you ever saw was their face and hands. So maybe the rules really are being relaxed, and kids just don't get an exemption any more.
It gradually became less and less common, but it didn't actually become taboo until relatively recently. Maybe 1996-1999 if I had to put a timeframe on it. This is back when we were approaching the millenium so there was momentum behind 'modern' reforms, and at the same time public opinion was mostly determined by glossy magazines like Newsweek. So around a lot of 'glossy' policy was enacted based on this formulaic and simplistic journalism style, which was good for covering the school shooting of the week but not so good for anything else.
EDIT: Corrected typo: Lets -> Let's
http://www.montrealsciencecentre.com/documents/csm/images/Im...
It was advertising this: http://www.montrealsciencecentre.com/exhibitions/sex-a-tell-...
Culture is your Operating System http://www.youtube.com/watch?v=9c8an2XZ3MU
Stuff to ponder about! :O