The protection of free speech should not include the advocating of committing criminal acts. To much music talks about mistreating women and taking drugs. The songs can be just as good without this nonsense. It teaches kids a wrong sense of values and has skewed social norms. People think bitch is a term of endearment.
While some music and lyrics may not be popular, it is an expression of free speech. Although you may hate what is being said, part of a free society means that people are free to say things you may not like. To ban music is to Go against free speech. It violates the constitution.