Well, Marc, once again, you have a point... up to a point
However, historical comparisons aside, the question for here and today is "do we really want our pre-teens and early teens to send around pictures of their boobs, crotches, butts and genitalia?" If we, as a society say it is ok, then all the power to Snapchat. But for the time being, it is actually illegal
I come from Europe, and I grew up seeing naked and semi-naked bodies on beaches and in public parks, including children and teens. The last encounter of that kind was, surprise, surprise, in the capital of the (still) puritanic nation, your home town (I suppose), Washington DC, around the obelisk, in the middle of the day (she was 18+ though).
I also grew up with David Hamilton's books. So you can hardly call me a prude. And yet I think that sexting among children is highly inappropriate and sends a wrong signal.