I find it repulsive that you equate a meeting between the President and a young American to child porn. It says a lot about your perverted mind, but more so the state of this forum by accepting these types of perverted threads to be made.
I don't equate it to child porn. The humor, whether you appreciate it or not, has nothing to do with children. It would be equally funny if it were anyone else who's head just happened to be level with Obama's groin. It's Obama's face that makes the joke. It probably wouldn't be funny if you could actually see her face, but given that it's just an anonymous scalp, it's pretty funny.
Again, the humor has nothing to do with the fact that it's a child's head at the bottom of the picture. I don't think anyone who laughed at it laughed because it was a child, they laughed because it's a dumb blowjob joke.