I'm sure there have been many that have tried to go after the National Geographic photographers too. They just failed.
I don't entirely remember if anyone made a stink about the little baby boy on the cover of the Nirvana - Nevermind CD, but under such loose laws, that would pretty much be covered under child porn.
How about seeing Eric Cartman's cartoon penis on South Park, or Bart Simpson's cartoon penis in the Simpson's movie?
I'm certain that people have flipped out and filed lawsuits over this, however, I do have faith that not every official takes these things serious.
I do believe that a lot of us have better sense about us. We are supposedly a centrist country in the USA, but we always have to hear about the idiocy of the far right/left jerks who feel the need to impose their views on everyone else.
I could, of course, be entirely wrong and we're all just screwed.