I think the FBI and the US tried to stop people like suge knight, because the rap industry became some king of black organized crime. When you have groups or people like suge knight, J.Prince, Harry O, BMF, Boobie Boys, many people from nyc, LA or Atl. Big drug dealers, this industry become some kind of crime families.
Lets be honest, the rap industry like many other industries is controled by gangsters.