"The point of modern propaganda isn't only to misinform or push an agenda. It is to exhaust your critical thinking, to annihilate truth." -Garry Kasparov.
And
"This constant lying is not aimed at making the people believe a lie, but at ensuring that no one believes anything anymore." This latter quote is, rather ironically, a false quote! (falsely attributed to Hannah Arendt). But I still think it contains truth.