iTunes “Clean” Rating.

I just noticed today as I was looking for a song from iTunes. I don’t really have that much of a comment, but since I saw this rating today… I have to say something. Perhaps it is my dismay, but as I looked for the soundrack of Carousel, I find that the album was rated Clean. Can it not be rated G or something more different sounding than Clean, so then does “Explicit” as I see in other songs on iTunes means Dirty then?