If it was produced in Greece, it was possibly made during the Greco-Italian war of 1940, when anti-Axis sentiment would have been strong. During this conflict Italian forces attempted an invasion of Greece, but met with a strong defence from the Greek army. The Greek counter-offensive actually resulted in Italian forces being pushed back into Albania, a protectorate state of Italy. It wasn’t until the German forces came to its ally’s rescue that they began a successful invasion. My interpretation of the cartoon is that it is mocking this event, from a Greek or British point of view.
Mussolini’s initial failure likely would have been viewed by Hitler as damaging to his victorious image, especially at this point in the war as Germany was proving a powerful enemy. Mussolini is looking rather foolish and Hitler crying, “do not break the wings of the windmill”, could be interpreted as his concern that the disastrous invasion would damage the spread of his ideology. Their failed invasion would have weakened the all-powerful image of Nazism, and with the swastika sails possibly representing a Nazi state, Hitler may have been worried Mussolini was a weak ally.
In any case, if anyone has any other ideas as what this could mean, we’d love to hear it!