You assume the CIA's only purpose is to conduct covert assassinations and overthrow "legitimate governments", as the OP is alleging. Which is just as far from

You assume the CIA's only purpose is to conduct covert assassinations and overthrow "legitimate governments", as the OP is alleging. Which is just as far from the truth as some of the lies the CIA has told over the years. The CIA has always been involved in intelligence gathering, which means among other things preventing terrorist attacks and discovering the capabilities of potential enemy nations. Like it or not, both are necessary tasks.