Article from Wikipedia about the Infamous "Clear Channel memorandum".
This was sent to Clear Channel stations shortly after the September 11 attacks, and it suggested songs that were not appropriate to play on the air. Read through the whole list. It's funny as fuck, and terribly sad at the same time.
Two of the most inspiring songs of all time, Imagine by John Lennon and Get Together by the Youngbloods were on the no-play list. I want both these to be played at my memorial service.
"Everybody get together, try to love one another" wasn't a message our corporate overlords wanted us to hear right then. It usually isn't, unless they can turn some profit from it. After all, the 34th of the Ferengi rules of acquisition says that "war is good for business", and the 35th says that "peace is good for business."
Of course with George Bush II's sycophants trying to spark off another Holy Crusade, "imagine no religion" would be off the table. Same with "brotherhood of man" and "imagine there's no country", and "the world shall be as one"; such incendiary lyrics! Let's not even get started about "imagine no possessions", while Georgie was telling everyone to go shopping.