And there you have it in a nutshell. If you cannot (or lose the ability to) directly control or influence what people believe to be "the truth", or if it looks as if certain inconvenient facts might get out into the wild, then you simply invalidate all potential sources by increasing the overall noise to signal ratio to the point where all information received is automatically regarded as being equally invalid. And once no one believes anything, about anything, anymore, you can do whatever you want, because, "Who would believe it?"