And why did the CIA depose an Iranian elected leader in the first place?
In 1953, Iran was very much in danger of falling into the Soviet bloc. Prime Minister Mohammad Mosaddegh was planning the nationalization of the Anglo-Iranian Oil Company (AIOC), and demanded a complete audit of their books. The British government and the US interests refused, and Mosaddegh was overthrown in a military coup organized in part by the US and Great Britain. This effectively returned rule of Iran to Mohammad-Reza Shah Pahlavi, the Shah of Iran, who asserted an absolute monarchy for the next 26 years, until deposed by Jimmy Carter. So Iran never fell into the hands of the Soviets.
Because "Democracy" in Iran leaves religious nut jobs running the country. I have no complaints regarding the CIA toppling the previous government. That is a big nothing in my opinion.
Jimmy Carter toppling the Shah was a horrible blunder. All he did was light the fuse to a world wide disaster of incalculable horribleness.
A million people are already dead because of Jimmy Carter. The Iran/Iraq war would never have occurred had the Shah still been running Iran. Iraq would never have dared attack an American Ally.