Hear no evil, see no evil, speak no evil... It didn't happen, because they can't see it, hear it, and thus can't speak it. They refuse to hear it or see it, so they can't be forced to speak of it. When they DO hear it, or see it, they deny it as true, so they still don't speak of it.

Soon the day will come when they can not deny it any longer. People had to see. Not just see it, but see it as being true.