The title is the key to this short poem. "Blowback" is a term for the unintended consequences of an action coming back on the one who took it, and the two brief stanzas show that idea at work in a quiet, unsettling way.
The first stanza sounds like a person half-listening to the news. "Who was taken by war" is flat and almost casual, as if the dead and captured are just another item in a list of headlines. There's a distance here, and the poem seems to be pointing at it.
The second stanza turns darker. Guns are "like strange teeth," an image that makes weapons feel like something biting, hungry and not quite natural. The speaker suggests that these guns "carry the enemy home with us," so violence doesn't stay overseas. It comes back in our minds, our habits, perhaps our own communities. The mood is cold, uneasy and accusing, with very little comfort offered.