I am pretty sure that everybody should be protected from would-be assassins. Why would a rapper be afforded any less protection from death threats or the threat of immediate harm be any different? This is a bit of a silly question if I am being completely honest and upfront about it.
Every person in this country has the right to feel safe and secure. It doesn't matter what that person does for a living. A celebrity has the same rights to be safe as anyone else. If there are threats against that person, society should protect him. Of course, that person shouldn't be instigating trouble, but if trouble finds him law enforcement should help him stay safe, because it is in society's interest to have a safe community.
No, rappers should not get extra protection. This particular genre of "artists" build their whole personal brand on the notion of being outlaws and gangsters with nothing but contempt for law enforcement. Then it is absurd that they would be entitled to extra protection from the very same system they despise so vehemently the moment they fear other gangsters turning on them.
In the case of Suge Knight, he does not deserve to have any protection after all the messed up things he did. He deserves every ounce of pain he gets for killing one of the greatest rappers of all time and another one that was supposed to be his friend. In other cases though it's like you made your bed, you kind of have to sleep in it. It all goes with thug life.