75 years of history disagree with you. Unless you believe the public told the CIA to arm the Mujahideen, overthrow Allende, invade Panama, recruit Nazis, traffic drugs - should I go on?
Even knowing now about al-qaeda and 9/11, arming and training mujahideen in afghanistan was not a mistake.
Ukraine having just applied for NATO membership, I would say you are comparing apples and oranges. Even the muslim NATO member Turkey that is hostile against the US despite the US giving them nukes hasn't backfired.
As for Congress, the idea that they know any more about the CIA’s activities than the average citizen is laughable.