On escape from the cave, Odysseus takes his men and the sheep they escaped with back to his ship, but he doesn’t just leave. That would be too easy. Instead, he starts taunting Polyphemus who is surprisingly good at echo-location and hurls boulders at the departing ship. These hit so closely that the waves threaten to drive the ship back to the island. Odysseus’s men are so freaked that they beg him to stop taunting Polyphemus.
Why? This seems like a no-brainer. It’s time for the escape. No need to spend time giving the finger to the guy, but Odysseus continues, finally revealing his true name to the monster.
This is no simply ego, though Odysseus is no stranger to the concept. It’s definitely in his nature to stroke his ego, but he also knows the benefits of discretion; he showed restraint in not killing Polyphemus in the cave, so this should be easy for him to do. But he doesn’t.
We’re actually caught up in something deeper. Polyphemus, upon hearing Odysseus’s name, recounts a prophecy that he had known, that one named Odysseus would blind him. But Polyphemus thought this would be another giant, someone with more physical strength then him. He never expected it to come from a shrimp like Odysseus, a mere human.
The prophecy demands Odysseus reveal his name to the cyclops. It’s mandatory. The Greeks believed very much in fate, but lest we think that there is a total absence of free will, it’s also Odysseus’s nature to do so.
We have to think about fate more roundaboutly. Odysseus would not have been the one fated to fulfill this prophecy had it not been in his nature to taunt Polyphemus. Likewise, it had to be someone clever enough to devise the plan, had the leadership skills to pull it off, and had the foresight to pull the naming shenanigans. Most importantly, it had to be someone who valued Zeus’s law of hospitality. That was the straw which broke everything.
And since we’re talking prophecy, we have to recognize that this was set up in advance. Three gods have the gift of prophecy: Zeus, Hera, and Apollo. The only one that matters in this story is Zeus since his is the law that the cyclopes broke. It is him that they openly disrespected as the god of strangers. And Zeus is clever enough to set up a fitting, yet roundabout, justice.
Zeus has no need to directly come down and smite Polyphemus. In fact, that would be too easy, and Polyphemus would never know of the severity of his crime, hubris. Zeus is naturally stronger than Polyphemus, so it would just be a beat down. However, Odysseus is so much smaller and weaker, that it is a just comeuppance to Polyphemus allowing his pride to get the better of him. He will forever remember that someone he underestimated, someone he thought was weaker, punished him for not showing proper deference to the gods.
Odysseus, as mighty as he is, and as clever, was used as a weapon of divine justice against the Cyclopes, showing not just the importance of revering the gods, but in the triumph of Greek, civilized life over barbarism.