I don't understand why that is offered as the take-away, because the article does not support it. It supports the take-away that smart people ask questions. The examples do not mention questions that challenge what has been said, but rather questions that result in a better understanding of what has been said.
Challenging people is not always the optimal way of exchanging information. When you think someone is wrong, asking questions to understand why they think something will work or is correct is sometimes much more constructive. This is in cases when it leads you to discover a different underlying assumption, a different main goal, a piece of information you missed, ...
I disagree. Asking questions is most often a way of challenging something.
For example, in the lecture hall example the students thought they understood the guest lecture and the only person to ask a genuine question was the tenured professor. The way I interpreted it was that the students accepted their understanding of the subject as "good enough" while the professor wanted to be 100% certain he understood the subject correctly. The professor challenged his own understanding.
Challenging people is not always the optimal way of exchanging information. When you think someone is wrong, asking questions to understand why they think something will work or is correct is sometimes much more constructive. This is in cases when it leads you to discover a different underlying assumption, a different main goal, a piece of information you missed, ...