Heck, I've hired people to teach me things, told them they were wrong, and learned the hard way, many times.
Not those who just punish anyone who dares. Then they're just not told anything but "yes, sir" until disaster strikes.
Wait, what? That's a ridiculous assertion, even taken as hyperbole. A huge percentage of people in power surround themselves with "yes-men", and are allergic to (even constructive) criticism, let alone direct disagreement.
Let's say there are a 100 people who actually interact with him in a professional context. Those are the ones that are yes men.