The closest working analogue I can come up with to MKULTRA's goals is cult indoctrination, and that only works so long as someone remains within the cult's sphere of influence.
People do break and defect to other countries all the time. It happened numerous times on both sides during the Cold War. Surely part of that process is convincing your captive or target that your side's "cause or mission" is better than the one they came from.
To what extent is that even wrong I don't know. What is a culture but a cult on a grander scale (as has sometimes been said of religion)? Not all cults need be death cults.
You can't just tell someone to do something repetitiously and they blindly follow the order. You would have to convince the person that if they didn't do something, the world would be worse off or something even more horrific would happen in a fictional alternate universe if that person was not stopped.
That the government wanted the public to know that these heinous experiments were taking place, just to try to convince them they didn't work, when it would have been much easier and more effective to simply never reveal them to begin with if they did work.
And if what the MKULTRA documents themselves say don't matter, then all of this is just a matter of faith. What is there to even discuss if the evidence doesn't matter one way or the other? Anything could be a coverup, false flag or misdirection.
I don't necessarily agree with what you're suggesting as being simpler. It may, in fact, be simpler to reveal the experiments and discredit them by using forged documents. Regardless of what may be simpler, I don't think it's scientific to take either position, which is why I prefer an agnostic stance when reading things that essentially require taking a faith-based position.