content: Account Deleted By User Its not to gather information on them, to bust them and arrest them, or "prevent terror" as they would probably say.  The real reason is simple - its the same reason why the Mongols were able to claim so much territory. They would destroy whole cities, and 100 more would surrender for fear of being razed. It is the threat of infiltration that is actually effective. People are so paranoid of being infiltrated, they refuse to collaborate at all (Not that I blame them). That's the real purpose, it is the most basic and effective PSYOP in the book.