I wanted to put my 5cents worth.
American anime is just now comeing out after pokemon was a huge hit. And american cartoonist wanted to get in on the new mainstream, witch happend to be Japanese anime(short for animation)So now when we see new series of American cartoons, they start to look more and more like japanese anime. That would be my guess. I think mostly the cartoons that they are makeing (teentitans,spykids,batman beyond,etc.) are for more younger kids. PG,K,E stuff. I would say most anime is PG-14.