In Book 22 of The Odyssey, why does Odysseus kill the servants?
On the face of it, it would appear that Odysseus' actions are quite cruel, and unnecessarily so. But one thing we should always bear in mind is that Odysseus is the king and his word is law in Ithaca. His servants haven't simply disrespected him or Penelope; in their disloyalty, they've broken the sacred bonds of ancient Greek society that bind everyone together.
Individualism as we understand it today didn't really exist in ancient Greece. Each person was defined to a large extent by the role they played in society. In the case of servants, that involved showing complete loyalty to one's master or mistress, and most of Odysseus' servants haven't done that. In doing so, they've challenged the very foundations of society; their actions were dangerous and so they have to be punished. For such transgressions, the only suitable punishment at that time was death. The servants may have derogated their responsibilities, but Odysseus cannot. As king of Ithaca, he is compelled by all that is sacred and holy to act out his social role as the source of all law and the dispenser of justice.
Odysseus kills the servants who have been disloyal to him in his absence. Betrayal by people one trusts is a motif that figures largely in the text, and loyalty is revealed to be one of the most important traits a person can possess. Odysseus is never betrayed by his wife, Penelope, or his son, Telemachus, both of whom have been incredibly loyal for twenty years, despite the trouble that this loyalty has caused for their family and their home. The text has also referenced the sad story of Agamemnon, the king who was betrayed upon returning from the Trojan War when his wife, Clytemnestra, and her lover murdered him. His son, Orestes, grew up and avenged his father's death when he killed his mother and her lover, and much is made of Orestes's filial loyalty to his father. To return home after a difficult and deadly twenty-year journey only to find that one's own servants have been disloyal would be upsetting indeed, and this is why Odysseus kills them.
Odysseus punishes the disloyal servants with death. Of the fifty maidservants in the palace, twelve have been unfaithful--such as Melantho, who has been sleeping with Eurymachus. These women are made to clean the great hall, which is splattered with blood, and then they are hanged. Melanthius is the only male servant who is killed; he betrayed Odysseus by obtaining weapons for the suitors from the storeroom where Telemachus had placed them, supposedly to protect them from smoke and to keep the drunken suitors from using them against each other, he had said. Recall as well that when Odysseus, disguised as the beggar, accompanied Eumaios the swineherd on a journey to the palace, Melanthius the goatherd had belittled the beggar and tried to kick him. After the battle Melanthius' body is mutilated horribly before he dies.
Odysseus doesn't kill all his servants in the first place. He does kill very many, though. He kills most of them for following the suitors (serving the suitors), and I guess because the more people to survive, the faster more soldiers would come. Also, he's kind of ticked off. (I would use a different word.)