Read the excerpt from Hemingway’s A Farewell to Arms. The major was a little man with upturned mustaches. He had been in the war
in Libya and wore two wound-stripes. He said that if the thing went well he would see that I was decorated. I said I hoped it would go well but that he was too kind. I asked him if there was a big dugout where the drivers could stay and he sent a soldier to show me. I went with him and found the dugout, which was very good. The drivers were pleased with it and I left them there. Hemingway uses vague pronouns and simple language to
I believe the answer is: reflect the reality of the characters' situation in a straightforward manner.
By doing this, Hemmingway able to separate narrator's opinion with the actual event that happen to the characters. This would provide the readers with the opportunities to analyze and judge the event by themselves without unconsciously influenced by the writer's opinion.