I'm not sure which is worse, there being no money or media attention in protest songs, or there being money and exposure in it. After all, it's not really that hard to rhyme "Bush" or "liar" (he burned his tush/his pants were on fire) and even "Osama" makes an easy rap rhyme for "yo mama." I'd rather not see again the equivalent of Rob Reiner as a hippie singing "blowin' in the wind" on an episode of Gomer Pyle, which I really did see. Rap began as a very crude, homespun and innovative style with lots of interesting artistic implications and anecedants, and its popularity has rapidly turned it into a stupid cartoon parody of itself.
My opinion is it's a good thing to be able to throw a rock and not necesarily hit a political protest singer, because it's artistically easy to fake it, to make your loose stuff look tight, and to make yourself think you're doing something important by cynically cashing in on a trend--just ask Bob Dylan about Masters Of War.