Because that resulted in the '79 Embassy hostage crisis. You want to start the clock in '79 because that fits your narrative. Ever hear of the term "Blow back". That is a CIA term for unintended events from a covert action. '79 was "blow back". I don't know if you ever read or not, but I can recommend a couple of books by chalmers johnson. The trilogy is called "Blow back, the cost and consequences of the American empire". spoiler alert, it was written before 9 11. Another informative Book about the Middle East is by Robert Frisk. Frisk was a Brit Journalists stationed in Beirut for many years and published in the London Times until Murdock bought the paper. He went to the Guardian when Murdock started changing his articles. The Book is "The great war for Civilization" . it covers history of almost all the Middle east countries from the end of the WW I until present times. You could learn a lot about Iran and the cause of the conflict between our countries.