Mossaddeq planned to nationalize the country’s oil business and break away from Britain who had been ripping Iran off for years. The British wanted a coup, but couldn’t conduct one on their own, so they whined to the CIA, who happily helped Britain continue to run the oil business in Iran.
You're leaving about 99% of it out, as noted in the post you are responding to. Western interests in wanting Mossadeq gone and having reason to stop his attempt to overthrow the system of government doesn't negate Mossadeq's actions.