In fact, too stupid to know they are retarded.
I recall reading a study about intellectual ability.
Stupid people were too stupid to realize they were stupid. They thought they were brilliant!
Smart people were smart enough to know they were ignorant about a great many things. Smart people tend to be humble because of their ignorance.
Lord...
Make me Humble.
The study you are referring to is known as the Dunnin-Kruger Effect. It goes a long way toward explaining Leftist thought...
“Stupid people were too stupid to realize they were stupid. They thought they were brilliant!”
“It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person.” Bill Murray, via Twitter https://twitter.com/biiimurray/status/603262580119842816?lang=en