Sorry if this has already been posted. But I thought it would be important. Give Credit to adamj004. You should all follow him for some good info.
He's reading the poems like they are from humanities perspective, which I believe isn't true. I believe these poems are from the Traveler's perspective. One part says something about giving an army their last orders or whatever, and then you go and they look for you. I think the Traveler gives this army of robots, the Vex their last orders and then disappears, travels back or forward in time to where he is now. Then the time traveling robots go looking for him. And they find him, now destroyed above your planet, and maybe that is why the Vex are your enemies.