Here's a thought experiment. Are you deeply offended by works of art such as Andres Serrano's Piss Christ, which depicts Jesus as seen through a jar of urine, or Chris Ofili's The Holy Virgin Mary, which shows Mary smeared with elephant dung? So offended that you think they ought to be banned and the galleries that display them prosecuted? No? OK, then try replacing the religious figures in these pictures with the sacred icons of progressive politics, people such as Martin Luther King and Nelson Mandela. How would you feel if you walked into an art gallery and saw an image of King submerged in urine or Mandela smeared with excrement?