Community
The imagery of community is offered in two ways. There is the normal community that the soldier hopes to return to (and of course the bitter reality he faces when he returns from an unpopular war), and there is the community he experiences in the hell of warfare. In his "underworld," the community has morals that are exactly opposite. Back home, people want him to be guided by emotional attachment to others. In Vietnam, the community urges him to be detached, violent, and hateful.
Warfare and horror
This imagery has a literal, physical component, and a psychological component that verges on true apocalypse. When the reader sees the soldier working to survive during the height of combat, the physical reality is heightened by the real threat of death, so that the true "imagery" of warfare is like a waking nightmare where demons are trying to drag him to hell. In other words, the experiences are ultimately traumatizing to his animal body and take him into emotional domains where emotional attachment to morality is inappropriate.
Justice and opinion
The book offers the abstract imagery of opinion and justice in the prose as Wolff tries to understand what it might mean to actually do the right thing. He tries to judge himself with various moral systems, but only betrays himself. It is as if the true 'justice' for him is just to survive, and by guiding himself with moral opinions, he betrays his ability to be flexible and do what it takes to survive, so the moment he imposes a moral judgment on himself, he disobeys it and is left scratching his head, trying to understand how motivation really works in his psychology.
The confused homecoming
The concrete imagery of San Francisco is used to imply a kind of normalcy that is strikingly opposite to the abstract imagery of PTSD that defines the soldier's real experience. The hippies who support the ethical treatment of people are ironically antagonistic toward the soldiers, so that the soldiers are treated as villains by the people who oppose treating others as villains, but this painful rejection is only visible to the soldiers themselves. They are greeted with more warfare as their communities make enemies of them, mistreating them for the sins of higher-ups.
