Twitter pointed me to a great article on How to work with "stupid" people by Jason Crawford. He's answering the belief that "people are stupid" with a wise redirection: maybe we don't understand them.
I consider myself reasonably intelligent, yet I have had no problem surrounding myself with people at or above my intellectual level. I’ve also had good relationships with co-workers at all levels of intelligence. Unless you’re a world-class genius (statistically unlikely), you are probably mis-diagnosing people as stupid.
His suggestions have to do with addressing the things I can change: me, and my understanding of the situation. The entire article reads like an expansion of the idea of "seek to understand, rather than to be understood" that many people learn from the Peace Prayer of St. Francis. Of course, Dale Carnegie and Stephen Covey talk about the same principles.
There is another concept underlying "people are stupid" in my mind. If the problem is not me - or totally outside of my control - then I can abdicate responsibility for correcting the problem. But this is not the case. What is my part in the situation? What can I do or change to make the situation work better?