While I wouldn't say that violence is exactly glorified (it is considered necessary, however), I would say that Homer's worldview was sufficiently different from ours to make his depiction of violence seem like glorification. I think that there are several reasons for this:
The war was, originally, a war of honor. Queen Helen was stolen (or went willingly) from the King Menelaus of Sparta, so he was honor-bound to go and get her back. His brother, the great king Agamemnon of Mycenae, was the overlord of many vassal kingdoms (such as Achilles' Pylos, Odysseus' Ithaca). This means that Agamemnon's vassals were required to engage in any battle that he chose to fight. Agamemnon is, by turn, required to help his brother recover his honor (and his wife). Not doing so would lessen the status of both Agamemnon and Menelaus -- and in Mycenaean times honor and status were extremely important! So, for the Greeks of Homer's time this war was both honorable and necessary -- by the customs of the day, it was not necessarily an aggressive action that the Greeks took upon the Trojans -- it was a logical consequence of the action that a Trojan (Paris) took against a Greek (Menelaus). By the standards of diplomacy of their day, there really was no other recourse, if Paris refused to give Helen back (which of course, he did).
Homer was a Greek and not a Trojan, so he would be likely to slant the telling of the war toward Achaean sympathies, but he nevertheless shows the human side of the Trojans, too (such as the scenes with Priam and Hecuba, and Hector and his wife Andromache and their son Astynax). The Trojans, to modern readers, are perhaps a more likable group of people -- perhaps because their social order was intact, while the Greeks were a group of warriors in an encampment -- but some of the credit for this must be given to Homer. Homer makes the death of Hector (Book 22) that much more awful because he has made Hector a real, round character, and not just a stock "enemy". While the death and the cruel treatment of the body are, without a doubt, told graphically, they are not gratuitous -- this was the most important single combat of the war, and the cruel treatment of the body is an important plot point. While Homer might have a different attitude about violence (that it was necessary to solve differences, and, perhaps, that the shocking thing about Achilles' treatment of Hector's body was not the violence of it but the sacrilege) but I don't believe he glorifies it. This is an opinion, however, and there are ample places in the text where violence seems unnecessary and cruel.
I think, however, that one of the stock phrases that Homer uses to describe death shows some of his attitude toward violence and death in war "And darkness covered his eyes" is the standard phrase applied when a man dies in battle. This poetic turn of phrase makes it hard, I believe, to take any death lightly. Homer, a man of his times and, perhaps, a true reporter of Mycenaean attitudes toward war and violence, seems to know the true meaning of a human life.