you dont actually think that makes you right? do you?
there is no such policy, if some local western unions (or the establishment that house them) have adopted it, likely because of some regional managers racist or xenophobic issues, does not make it a western union policy nor does it mean that western union has a "secret agreement" with the federal government.
in point of fact, all you have to do is point out western unions actual policy when you send your money. If they refuse to send report them to western union head office (which is what you should do- middle managers dont make policy regardless of what they think).
as a note- its always better to use WU that is not solely a WU or a check cashing/payday loans place (as they may have their own ID requirements).
the ones in supermarkets tend to have less bullshit.