The equating of looking at pictures with rape is a very common argument. I remember after the last war there was a very popular book called "Scourge of the Swastika", very widely read, which detailes the activities of the nazis, torturing etc. Reading that book, I can assure everyone, is very different from actually torturing someone. Not everyone who read that book progressed to actually torturing people; and not everyone who has read Agatha Christie, or looked at the pictures in true-life crime books, progresses to murder.
If Gary Glitter has passed beyond an indecent obsession with an unsavoury subject to actually practising the activity: well, let him be tried and dealt with. But not with the kind of witch-hunting that some people are trying to organise. Remember the mob that tried to beat up the pediatrician.