Unfortunately propaganda makes very good use of the way we humans learn stuff. If you repeat something often enough then people will start to believe it. So if all you ever get to hear is one point of view, then that will be your point of view. Of course this won't work on everyone at the same time, but it works good enough for governments to be able to steer the people in directions that they want. You can see this happening time and time again in history, people are pissed off, there comes this guy who blames some other people, now these other people need to die. It's so depressing..