A large part of the feelings of war are presented in the way that Whitman writes, not necessarily what he says. The broken sentences with dashes and ellipses make the reader feel as if there are bombs falling near them, as if they are ducking for cover or having to drop their voices to avoid being detected. Also, his points of narration without interruption harbor these feelings as well. These points of calm are broken just enough with emphatic statements that we as readers feel our safety net has been disturbed and our privacy invaded. Whitman also employs form to relate to his readers a feeling of chaos. "Then the camps of the wounded--O heavens, what scene is this?--is this indeed humanity-these butchers' shambles? There are several of them. There they lie, in the largest, in an open space in the woods, from 200 to 300 poor fellows--the groans and screams--the odor of blood, mixed with the fresh scent of the night, the grass, the trees--that slaughter-house!" By using dashes and especially exclamation points (that reporters are often encouraged not to use because they make writing appear too dramatic), Whitman makes us feel that we are witness to this scene, a scene that could've been constructed because it doesn't really convey particular facts (not who, when, where, or even how many [200-300 is a pretty big estimation]).
Herr is able to use this same kind of writing, but often without the exclamation points except to emphasize what someone says. He rarely adds them in his own musings. In a way, Herr's understatement of emotions makes his writing more real to his readers because at first, I'm sure we all believe 'we can handle it.' He thinks he is capable of doing things around the bases and should be regarded with at least a common decency by the men around him. Yet he is (at first) surprised and then understands that these men are here fighting, not just for their country or someone else's country or freedom; they are clawing and beating against death that follows them. When he is able to get on the chopper and leave these fields, they are not; that is their duty.
Herr also uses quotes (Whitman does not). He is able to point to facts and people and distinct conversations, making it clear that he was present on the field. Part of his strength here is not identifying the soldiers he spoke to. In the same way that soldiers are unidentifiable in the field of wounded and dead, Herr has chosen not to identify these men.
I do think that Whitman and Herr use organic style. They both exemplify the horror they felt (or would have felt, because Whitman wasn't present) by witnessing such massacres and feats of humanity. If this had been written about an afternoon of merry-go-round watching, the exclamations and conversations would have been much different and dictated another attitude and tone. If the subject had been children, there would have been much more circular conversation, music playing in the background, and light humor- all implied through the description of the scene and wording. Instead, readers smell the blood and are forced to sidestep fallen comrades as they read through Whitman and must hush their voices and keep their pleasures at bay while crawling through the jungle with Herr.
Is Whitman's style and writing less powerful because he does not use quotes? Would we believe him more if he did? If we know he wasn't there, would we want him to fabricate quotes to add power?