That is a good example. Talk of creating jobs as a benefit, rather than a cost is quite common. But is it confusion or malice? It is hard for me to imagine that economists would publish such a book without having it pointed out to them. The audience certainly is confused. Henderson says "Almost no one spending his own money makes this mistake" and would not generalize to people's capacity for abstract thought.

The original question was how much information to extract from the conventional wisdom. I do not take this as a reason to doubt the conventional wisdom about personal decisions. Partly, this is public choice, and partly because people do not address externalities in their personal decisions. Maybe any commonly accepted argument involving economics should be suspect, though the existence of the very well-established applause-line of "creating jobs" suggests that there are limits to how to fool people. But your claim was not that people are bad at physics and economics, but at the abstract thought of decision theory.