In the world at large people are rewarded or punished in ways that are often utterly random. In the garden cause and effect labor and reward are re-coupled. Gardening makes sense in a senseless world. By extension then the more gardens in the world the more justice the more sense is created.
Is human nature basically good or evil? No economist can embark upon his profession without considering this question and yet they all seem to. And they all seem to think human nature is basically good or they wouldn't be surprised by the effects of deregulation.