Why is the water buffalo's death more emotional than the human deaths depicated in this novel?

The men's friend and fellow soldier Curt has just been killed; the company finds the baby and they bring it back to camp........... one minute, Rat is attempting to feed him, and the next he's unloading his gun into the helpless animal. The men are shocked; they're amazed. In essence, their feelings are served up quite well by Mitchell who says, "Well, that's Nam. Garden of Evil. Over here, man, every sin's fresh and original."

The baby water bufflo's death is more emotional because it shows them how unfeeling everyone has really become. Death is everywhere. Their friends are dying, they're killing to survive, and yet that little buffalo became smething they could save, but they couldn't even do that because some of them were so emotionally over the top and distraught over over what they'd been experiencing.