If those in the positioning of governing achieve a sufficient disdain for the governed, they convince themselves that the populace is too stupid to pursue truth. You may find this a stretch, but it's roughly consistent with calling the voting public "deplorables."

I think it's already been touched on, but the reason Germany made it illegal is to prevent Nazism from happening again. The German government wasn't trying to hide anything. The German government was trying to prevent Nazi's from hiding something.