Listen, you just don't realize that under the definition of "Arab", Iranians can't be considered a part of such a group. Iran was ressurected (all though I argue that Iran always existed even though it was "conquered") with changes, but all countries change. In the end, a person can't characterize something which it isn't at all (aka Arab). Iranians revitalized Iran and set it in direct opposition to Arabs, and conquered the Islamic caliphate to show that. Ferdowsi, writer of the nation's epic book The Shahnameh was very opposed to Arab influence on Iran which swayed Iranians from their original culture. Now it represents pretty much what Iranians stand for, their culture and try to rival all Arabs. If this dosen't constitute an independent entity I don't know what does. The Persians that moved to and existed in Mespotamia, Syria, Greece have all become Iraqi, Syrian, and Greek because they subscribe to those country's culture, language, and history. So no it isn't at all contradictory to call them that. Furthermore, nearly all people in the Persian empire were not intruded upon. They were free to practice their religion and keep their integrity as a state. It was a loose coalition in other words. As such, I don't know how, in any way, those Greeks weren't independent from Persians. Taxes is one thought, but I believe I read that Persian taxes were less than Mespotamian or Egyptian.