Sputnik, a hammer and sickle emblazoned on its side, floats through space in the film's opening scene. Many of the film's references are more sophisticated than is usual in animated children's fare.
Conformity is uncool.
Distrust the government. Patriotism can be a cloak for self-interest. It's anti-nuclear only in the atomic sense. While Hogarth is being besieged by surrogate-father figures, the hapless giant is discovering that he has the capacity for destruction. We can't tell you what he decides, but we can tell you that if this is an allegory for pacifism, it backfires spectacularly.