It's linguistic profiling, and it's the only reasonable way to enforce the export law.Only if you are being a completely stupid and bigoted bastard. Otherwise the only sane way to enforce an export law if you are a company, is to not deliver items to that country.
Everything outside that is up to governmental customs and border control and no court would enforce not selling IPads to Americans who are born in Iran and speak Farsi. Otherwise it is nothing less than apartheid.
The policy quoted states:
the exportation, sale or supply from the U.S. to Iran of any Apple goods is strictly prohibited without authorization by the U.S. government.
It does not say you are not allowed to sell them to people who speak Farsi, even if they were born in Iran. It just says that Apple is not allowed to send them out of the country. You could possibly also claim that you are not allowed to sell directly to current Iranian citizens, as they could be said to represent Iran, although this would still be reasonably open to question, especially if they have a green card, which are available to current Iranian citizens.