What do you think is the message Homer wants to tell us by giving a vivid description of the bloodshed and carnage of the Trojan War?

Homer wants us to overview about Trojans war to let us know and understand the origin of that war. It would not possibly happen if the two goddesses are willing to accept that they were defeat, and not chosen to be awarded a golden apple. If they accept the reality and their losses, the war between Trojans and Achaeans has not been possible. The peaceful of their kingdom was still and also their relationships as Goddesses.
Homer also wants us to know that how heroes suffered and sacrifices for the victory to attain freedom and a peaceful Kingdom. So, it gives a very big and unforgettable lesson to us people around the world. And to realize that it provided us with explanations, have influenced our vocabulary, have entertained people for many generations, and continue to teach us many lessons.