Dystopias create "worst case scenarios"out of current social, government or technological trends in order to:
question the existing social and political systems.
believes or feels that something is terribly wrong with the society in which he or she lives.
The dystopian world is not criticize itself, but is a way to criticize some aspects of the actual world or society the author lives in and doesn't like, by showing how those aspects are a seed to something worse if not changed.