Not everyone brainwashed is stupid either. Some are actually considered intelligent. The ones I know simply believe that if crimes had been committed, the perps would have been held responsible. An example given to me was of the HRC email investigation and Benghazi. "If she did anything wrong, they would have uncovered it". How do you argue against that?
As far as MSM propaganda and collusion - they can't believe a conspiracy so big could be kept a secret, even though the logic behind the conspiracy being kept secret makes perfect sense. Some just aren't as dubious of "authority" as others.