Because he doesn't understand anything

[ShazzieB]

42. Hard disagree.

We think he's stupid because he IS stupid. He may have once been smart about some things, but those days are over. Dementia is rapidly eroding whatever edge he may have once had. These days, I think he's operating on pure instinct, continuing to do things that used to work for him and continually baffled when they no longer work.

I don't think he knows what he's doing at all. When it comes to the complex things involved in running a country, like international relations, trade policy, even interacting with other world leaders without embarrassing himself, he's so out of his depth that he might as well be at the bottom of the Mariana Trench.