I hate the leader of Iran. He is so stupid.

If people like or agree with someone, they don't often question their intellect.
When they are not in agreement, they consider them stupid.
After a long debate or discussion, I can see how this may be relevant.

I want to understand why people consider either leaders to be stupid/dumb, or themselves to be smarter than many leaders.
Some inevitably smarter than others.
How is their a justifiable way to think that these people have gotten to where they have gotten, with out having intelligence? Note -with out being an heir to a thrown.