If this and similiar happening is true, then IMO, it has to do with couple of things. Kids are being exposed to all kinds of music mainstream crap these days, especially pop/hip-hop/rap etc. videos "featuring" this kinds of footage. On top of that, what is even more scary is that mainstream music industry has pre-teens/teens as their main "target audience", and in videos it basically encourages them to experiment with this sort of things, as Nebula said. But they won't stop producing them, since it brings them in pile of cash.
So, it all comes to parents not taking care about their children, due to not having enoughtime. They are chasing their careers in order to secure theirs and their children's future. Although, that sure isn't even a remotely good excuse, but you can see where it is coming from.
