What kind of losses? Loss of what? If a majority of people incurred more losses than gains in their lives, we'd all have starved to death tens of thousands of years ago.
OK, fair enough its a sort of definition or has the superficial form of one, but it's not actually saying anything.
From the article:
“A stupid person is a person who causes losses to another person or to a group of persons while himself deriving no gain and even possibly incurring losses.”