It's quite possible that part of Amazon (e.g. AWS) is doing defense contracting, and that the U.S. Department of Defense (DoD) is making Amazon jump through hoops Amazon haven't the stomach for. I'm aware of at least one DoD contractor that will hire Iranian born people, but there's a special background check that DoD requires, and, assuming that turns out OK, there are still some data/projects they're prohibited from getting access to. DoD assumes Iran will blackmail those with family in Iran with the welfare of their families, forcing them to breach confidentiality agreements.