Stupid is often a product of dumb plus narcissism, a stubborn unwillingness to learn.

As the other threads dog pile on critism, one would probably do well following the implied advice of avoiding what oneself considers a stupid person, rather than granting them the benefit of doubt. Their poor decision making will side effect you.

Sounds like this goes against the old saying "I may be stupid but I'm not dumb", i.e. I'm not book smart but I have common sense.

This is the distinction Dungeons and Dragons 2nd Edition rules made between the Intelligence stat and the Wisdom stat. Intelligence was book smartness and wisdom was common sense and general understanding of the world and people. Wizards were intelligent but not necessarily wise, and clerics/druids were the opposite.

>> Sounds like this goes against the old saying "I may be stupid but I'm not dumb", i.e. I'm not book smart but I have common sense.

There is another saying "You can't fix stupid" so giving them more knowledge doesn't help, it just expands their sphere of influence.

There's an old Chinese/Japanese proverb about this even.

"Baka ni tsukeru kusuri nashi"

The medicine which can be applied to stupidity, does not exist.