There are two (maybe three) great origin myths of the western world. We begin our stories either with the ancient Greeks or with the ancient Jews. Sometimes we get sophisticated and say that "we" as the west are the merger of the two -- a third story frame. At the heart of the troubled subject of Iranian/western relations is the simple fact that the Persians are the 'bad guys' in BOTH of the underlying two myths. The Greek narrowly escaped being swallowed by the Persian empire. The contemporaneous Jews did not escape that fate, although thanks to Esther they survived it. Yes, there are other more recent sources for the animosity, and there is the sociological fact that our elites will always want us to have foreign enemies. It is better we aim our bile at foreigners than at the domestic elites themselves! So, at any rate, the latter believe. Beyond all that: Iran is Persia and Persia have always been the enemy. Since long before there was Islam.