Simply this, children need idols. In some cases "Rap Stars" happen to be those idols; it is pretty much clearly stated in most rap to smoke pot, disrespect women, drinking, etc. Although it is not a good thing in most cases it happens.
It is that same as teenage suicide through the influence of rock music. Do not get me wrong I am not saying those types of music are bad, but for certain people they take the meanings to literally. In turn causing themselves to do something pretty foolish.
I could be wrong, but that is my view on it.