The U.S. has long had Iran virtually encircled as a result of the American occupation of Afghanistan on Iran’s Eastern border, its invasion of Iraq on its Western border, its NATO ally Turkey hovering on Iran’s Northwestern border, some degree of military relationship with Turkmenistan on Iran’s Northeastern border, and multiple U.S. client states sitting right across the Persian Gulf (Kuwait, Saudi Arabia, the UAE, and Bahrain, where the massive U.S. Fifth Fleet is stationed) … //
… I’ve cited that passage before, but it really does explain so very much (and that form of thinking extends beyond nationalism to all tribal loyalties). It’s how a country that has repeatedly invaded, occupied, bombed, and killed civilians in numerous other nations over the last decade can look at a country that has done little or none of that (but has been practically surrounded by all that aggression) and be convinced: they are the Evil aggressors and must be stopped at all costs.
UPDATE: One other point: whenever you dare to suggest a comparison between the United States of America and whatever country happens to be the New Hitlers of the moment, you get accused of moral relativism. That has always struck me as so bizarre, because moral relativism actually refers to precisely what Orwell described: Actions are held to be good or bad, not on their own merits, but according to who does them, and there is almost no kind of outrage — torture, the use of hostages, forced labour, mass deportations, imprisonment without trial, forgery, assassination, the bombing of civilians — which does not change its moral colour when it is committed by ‘our’ side. As Rudy Giuliani said when asked if waterboarding is torture: It depends on who does it. That is moral relativism. (full text).