It’s actually not. People who are brilliant in one topic could be easily stupid in another. Picasso couldn’t do calculus. Fish can’t climb trees.

It’s very rare to find an actual stupid person. Uneducated, sure. Ignorant, you betcha. But to be actually stupid across the board, you either need to have a real genetic deficiency, or be stubborn in your ignorance.

And I found that people who think others are stupid very often do so because they are ignorant themselves about the multiple types of intelligence.