Most people prefer to believe that their leaders are just and fair, even in the face of evidence to the contrary, because once a citizen acknowledges that the government under which he lives is lying and corrupt, the citizen has to choose what he or she will do about it. To take action in the face of corrupt government entails risks of harm to life and loved ones. To choose to do nothing is to surrender one's self-image of standing for principles. Most people do not have the courage to face that choice. Hence, most propaganda is not designed to fool the critical thinker but only to give moral cowards an excuse not to think at all.
h/t Michael Rivero