If you take off your cynicism-tinted glasses, it's the story of how community is more than the sum of its parts, and how it sometimes needs a "beautiful lie" as a catalyst (like justice, or freedom!)
At each step, the participant (especially the first) is deliberately misled to believe that they can secure valuable soup for less-valuable ingredients.
It is not an appeal to their better nature--in many tellings the travelers have already tried that--but an appeal to their baser nature. For it to be a positive story, one must accept that the ends have somehow justified the means.