It does not seem everyone from a particular sensitive country get this kind of treatment. Even many claim that when a USA has a bad relationship with a country,
in many respects, iit become easier for individuals from that country to get immigration benefits from USA. It is pathetic to take advanatges of that but many claim
that is the case.
You're right. However, the OP's treatment doesn't necessarily reflect the actions of USCIS as a whole. It's quite possible that the IO or his supervisor harbors resentment toward Iran and is taking it out on the applicant.