I think it also shows how savage those times were (not that the Trojan War necessarily happened at all). The poem celebrates death on an epic scale. I assume that the Trojans would have be just as destructive had they won. It was what they did back then (or at least the did in the mythic world of Homer). The argument between Agamemnon and Achilles at the beginning is over the possession of a woman who was Achilles' prize of battle. That in itself seems very ignoble, but it was the way back then. The story has a very casual attitude about killing, raping and pillaging.
Probably so, although according to Homer Poseidon & Athena, at least, were offended enough by the sacking to see to it the Greeks had one helluva time returning home.