If politically infused music is denied airplay, music reviews or festival stage time because it is considered "politics" rather than "art", then there will be no music left to ban. It will never reach the surface anyway, not to the larger audience. I believe that there is a high degree of censorship in the west, most importantly in the form of self-censorship among musicians themselves. This is why what you hear on the radio is - increasingly often - pure and toothless entertainment. Almost by definition, there's nothing left in pop music worth banning.