The scanners "look through clothing!" Well, duh. That's how you find something hidden under clothes. And all the scanners reveal is the shape of a person's body.
We try so hard, with clothing, to mask the true shape of ourselves. Have a bit of a belly? Hide it under loose-fitting clothing. Breasts a little saggy? Cantilever them into place with a supporting bra! Got a big butt? Tuck it in with tight undergarments.
But really, only the first of these three secrets would be revealed by a body scanner. The only thing you can see with the scanner than you can't see with -- pardon the pun -- the naked eye is an unbroken outline of the body. That, and any bombs or weapons you might have strapped to it.
O.K., you can see a person's butt crack. Does anyone deny that we all have one? Isn't it worth it if there's a pistol next to it? Maybe you can see, vaguely, the shape of a person's genitals. But do you really think that an airline security person, after viewing 10,000 grainy, blurry images of a man's penis or a woman's pudenda, wouldn't be too terminally bored to get excited by the sight of one more? If it were me, I'd be far more interested in whatever that odd package is hanging next to the routine Nigerian penis. That's exactly as it should be, and if that were the man with a ticket to the seat next to me, I'd walk through the scanner gladly, even stand next to him in the scanner so the security personnel had a good look at what normal looks like. Heck, I'd gladly even drop trou if that's what it took.
The security guard will forget your hidden body girdle, your short penis, your cesearean scar (if those show up) in half a second flat. That's a pretty painless price to pay to keep from getting blown up at 10,000 feet.