Dr. Mossadeqh was not running a "democracy". Post WWII Iran's political space was far more complex than the caricature presented since the fall of the Shah, and sans British instigated support for counter-coup to remove Mossadegh with help from USA, a quite significant chunk of Iranian military and society, including the Clergy (who were already using terror in Iran, btw), agreed with the American analysis that Mossadegh would merely precede a Soviet controlled Tudeh takeover of Iran.