Re: We know they lie
They understand the principle just fine. They also understand that it has little actual force in the real world. History and psychological experimentation provide ample evidence that audiences are not, in general, strongly conditioned by a history of falsehoods; that the "Big Lie" and other non-logical rhetorical techniques are far more successful at persuading people, in general, than logic and reason; and that a strategic mix of silence, deception, and limited truth (carefully couched) has been very successful in achieving their aims1 and shows no signs of weakening.
For all the ink and breath spent on the subject, I see no signs that the Snowden revelations, for example, have done any significant damage to government intelligence agencies or broadly speaking to the parasitic private industry they contract out to. That doesn't mean those revelations were not useful, but their utility does not appear to include any dismantling or even reduction of the surveillance / police state.
(And the same is true of other, longer-standing efforts in this area, such as Cryptome. John Young may be a class-A curmudgeon,2 but he's been publishing stuff since long before Wikileaks was a gleam in an attention-seeker's eye. Yet still we have steady encroachment on civil liberties and other abuses of power. Ditto Watergate, the Pentagon Papers, etc.)
1First of which is the continued existence and burgeoning budget and power of the intelligence industry, of course.
2And visitor to these hallowed pages under a pseudonym? Perhaps.