Some people are very good at doing psychological profiles and analyzing people’s body language, rather than their superficial remarks or words. It’s also important to understand the offense based tactics and strategies a person uses.
For example, a person at the top of his game could easily see when two serial killers were trying to manipulate women at a prison. But the women and the weaklings, the people who prefer a sugarly version of reality or who merely overestimate their capabilities, cannot see it. They don’t want to see it. They couldn’t see it even if they did want to see it.
Dunning Krueger effect may be enough to explain, but I think it is more onion layered than that. Hussein often talks about Republicans or the white police as being stupid. That is due to much laziness and incompetence on Hussein’s part, the inability to see talent in others because he himself lacks it. However, when American patriots look to Hussein, they see his incompetence, because the American patriots are not experts or ruthless agents when it comes to evil power, so they cannot see that talent in other people. They underestimate them, as such.