The reach of propaganda has increased immensely though with technology. Everyone has a little box in their pockets and many of them use it to read propaganda many times per day. Not true in Roman times!
The idea that more educated people are easier to propagandize practically goes against our self conception and mythology but that doesn't make it less true.
I am pretty sure most people believe that their education insulates them from propaganda or lets them decipher what is true or not but that is actually part of the problem. If what they read lines up with what they want to believe, viola.