"The Man He Killed" isn't your average war poem. It's personal, brief, and haunting. There are no grand generalizations, no waxing poetic about glory and sacrifice, and no grisly, graphic battlefield scenes. It's just a guy, telling someone about the fact that one time, he shot a man down. It's as simple as that. Except that it isn't.
This is not an anti-war poem. It's merely pointing out a fact of war—that men have to kill each other for reasons they don't understand.
This is totally an anti-war poem, because Hardy is pointing out the senselessness of these deaths. Men who could have just as well have been friends should not be killing each other for the sake of some cause. They're not really foes in the first place.
To be perfectly honest, Shmoop doesn't have much evidence that the speaker of "The Man He Killed" feels guilty at all. But we're betting he does, since he seems to stumble over his words as he describes the scene. And it only gets worse from there, as he tries to justify the death with shaky reasoning and dead-end excuses. In the end, the real guilt comes from the fact that he killed a man who was just like himself. How in the world do you clear your conscience after something like that?
The speaker feels less guilty by the end of the poem, because he understands that the man tried to kill him, too. They were a lot alike, after all.
The long dashes, internal rhyme, and repeated because and foe show us just how guilty this guy feels. He can't face the truth.
You might think that on the battlefield, everyone's an equal. After all, everyone's equally likely to kick the bucket, right? Well, maybe not. After all, the speaker of "The Man He Killed" is an enlisted infantryman, which means that on the battlefield, he was on the front lines, taking orders from someone way in the back. And in all likelihood, the fact that he was an enlisted infantryman probably stems from the fact that he wasn't the richest of dudes on the home front. So it turns out that, like everything else in life, the battlefield isn't always an even playing field.
The real lesson of this poem is not that war is Hell, but that war is Hell for the lower classes.
The fact that this guy may have joined up because he was unemployed tells us that it's the lower classes that suffer most in war.