It is clear that the speaker of this poem views war as something terrible but something that must be endured to the best of man's ability. Note how the opening two lines offer a very interesting description of the break of day as dawn descends on the battlefields:
The darkness crumbles away
It is the same old druid Time as ever...
By comparing the present to the "old druid time," Rosenberg is making a comparison between the time of the Druids, and human sacrifice, and the way in which other humans are sacrificied in great numbers during the war. Of course, daybreak was a time that was feared by soldiers because of the visibility that it gave and the uncertainty of whether or not you would make it through another day. In addition, it is clear from the speaker that war is so terrible that there is hardly any guarantee that you will make it through alive. The description of war, of the "shrieking iron and flame / Hurled through the still heavens," offers an almost apocalyptic vision of war and presents man's efforts in the face of that as being rather meaningless. War is presented as a mighty external force that man cannot do much against, except try, in vain, to survive.