Censorship of gangsta rap and the enforcement of it is not feasible. It also goes directly against our right to free speech. If people do not want to hear gangsta rap, then they can choose to not listen to it. If parents do not want their kids listening to it, then the parents need to be sure that their kids are not listening to it.
Censorship of gangster rap violates freedom of speech. Furthermore, what is offensive to one person may not be to another. The arguments about how to define porn would likewise apply here. Freedom of speech should not be censored. Ratings and warning labels are enough to allow people to decide for themselves. Although, even ratings cam be subjective.