Final answer:
Vonnegut described a future society to provide a warning and create contrast with the present day.
Step-by-step explanation:
Vonnegut described a society 120 years in the future in order to provide a warning of what could happen if present-day society does not address a problem. By setting the story in the future, Vonnegut creates a sense of distance and minimizes the risk of offending readers. The future setting also allows for a sharp contrast between present-day society and the hypothetical future society described in the story.
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