Dennis Prager has his panties in a wad because rap artists swear too much, but are still intellectually capable of making good music. I'm reasonably certain that my comment on the article won't make it passed the screeners at the National Review, so here are my thoughts, with notes.
Why is it such a big deal that a music video by a black artist has an all-black cast? No one's panties ever get in a twist about a music video by white artists having all-white casts. [Notice how he never actually illuminates why this is a problem.]
Further, I will speak to the only song on the list I have heard. Eminem's song "Love the Way You Lie" is an amazing portrayal of the emotional tumult one goes through when involved in an abusive relationship. As such, it is not only appropriate, but necessary for the F-word to be used in the lyrics. The thing about art is that sometimes it deals with things that are icky, because art is a necessary expression of the world the way it is seen by the artists' eyes. Pieces that deal with volatile subject matter necessitate swearing in order to get the point across that sometimes life is awful.
When an artist is telling their own story about how their lives have been challenging, it isn't simply moral degradation that causes said artist to swear, but the fact that they are reflecting a culture that is degrading. Art is not something that is subject to the delicate sensibilities of Dr. Prager, because the minds of artists don't get run passed society's self-appointed content-screeners before being published; just as what actually occurs in their lives that inspires these depictions is not passed by anyone, save g-d, perhaps.
In truth, it is not swearing which belies the moral degradation of our society, it is the poverty in which too many Americans grow up that demonstrates that we are a broken nation. It is the unwillingness of certain groups of people to accept the basic humanness of other groups of people, simply because their skin is a different color, or their religion is different or because they love a person of the same gender. You want to talk about moral degradation? Spend a night on the street with a homeless vet whose mind was annihilated during war. Take a look into the lives of teenage girls who are forced into prostitution either by coercive violence or because an adult got her hooked on meth. Then tell me it's inappropriate for an artist to repeatedly use the F-word in a song.
Rap music isn't the cause of moral degradation and it's not even the result of it. It's the artistic depiction of the horrors that escape persons of privilege, like Dr. Prager who cannot see four feet in front of their own faces.