It is vital when reading this to understand that it is descriptive, not proscriptive. It defines a particular definition of stupidity, a very utilitarian one, and then proceeds to classify various portions of the world based on that definition.
It does not spell that out right at the beginning, or even necessarily at all. But it is not discussing all possible uses of the word "stupid". "Wasted potential" definitely doesn't work for discussions about active harm being done (at some points).
(As such, another common critique I see is trying to decide if it's "right" or "wrong", but that's the wrong question. As it proposes a definition, one that I think undeniably does have the ability to be applied to the world, the question is rather if it is useful. I have found it so, but that's debatable. But that's at least the correct debate.)
The article also discusses stupidity as an attribute of people, not actions.
I assume anyone who has had any experience with the world at all has "cause[d] losses to another person or to a group of persons while himself deriving no gain." Are there any non-stupid people?
It does not spell that out right at the beginning, or even necessarily at all. But it is not discussing all possible uses of the word "stupid". "Wasted potential" definitely doesn't work for discussions about active harm being done (at some points).
(As such, another common critique I see is trying to decide if it's "right" or "wrong", but that's the wrong question. As it proposes a definition, one that I think undeniably does have the ability to be applied to the world, the question is rather if it is useful. I have found it so, but that's debatable. But that's at least the correct debate.)