The soldiers in this poem are crippled, mentally and physically overcome by the weight of their experiences in war.
Did you notice how unwilling our speaker seems to introduce himself (and his fellow soldiers)? We're almost all the way through the second line before we (the readers) hear who "we" (the subjects of the poem) actually are.
In fact, we get simile upon simile before we are acquainted with the subjects of this poem.
We hear that they're "like old beggars" and "like hags."
The speaker's searching for images that his reader can understand, as if he's convinced that none of his readers will be able to understand how horribly twisted and deformed the bodies of the soldiers have become.