I don't think there should be censorship in the form of an official board that sanctions what art is or is not to be made. I would expect that would be very bureaucratic, having to present every piece of art to a licensing committee etc. Eventually, an 'artist' wants his work to be displayed, and will present it to others. The authorities should obviously investigate each case where they fear criminal abuse has occurred to the subject of the art, as they probably do already. I expect that most paedophiles and abusers of women don't try to draw attention to their crimes by promoting them publically as art displays. I don't think there is any case to make for censoring art on non-criminal grounds. Art should be as explicit, blasphemous, gruesome, or politically biased as it wants to be.
On a similar vein, I heard a story once that Salvador Dali pushed his best friend over a cliff when he was nine years old, to see what happened when people die. Is Dali's art more valid or less valid when we know he was the equivalent to James Bulger's killers?