Is this what "deprogramming" a brainwashed person is? Moving them from the position of their captors' propaganda to a position within the propaganda believed by an entire society?

Patriotism being one example of this type of propaganda -- the idea that some of us are better than others because we were born on one side of a line in the dirt.

This is why I find the concept of brainwashing/deprogramming fascinating from an epistemic perspective; you're essentially substituting one set of axioms for another. And it's often hard to determine who occupies the epistemic higher ground, since all camps will claim to do so. For example, liberals think Fox News is brainwashing people, and conservatives think academics at liberal schools are brainwashing people. Sometimes the only thing you can use to figure out what's true is secondhand knowledge (via a network of cognitive authorities that you've chosen to trust) plus your own judgment, which itself has inevitably been influenced by some set of chosen axioms.

And often each system of beliefs has epistemic protection against debunking... for example, religious believers may view debunkers as agents of evil/Satan, while conspiracy theorists may view debunkers as agents working on behalf of the conspirators. In both cases, one has a "rational" reason to be skeptical of (or even outright disregard) any arguments that attempt to undermine one's axiomatic system.

Humans seem to gravitate toward certainty and consistency the way moths fly toward light. It's an emotional craving, and in order to be rational we have to be exceedingly comfortable not knowing things (and realizing we often don't know what we don't know).

The more a person seeks the opiatic, emotional feeling of fake knowing, the more receptive he is to religion, political brainwashing, conspiracy theories, prejudices, social authority structures, etc.

Humans don't work the way you think they work. We don't hold sets of axioms and reason from them to build a logically consistent set of opinions in such a way that changing someone's axioms carries the whole weight of their belief system along with it, like making a code change in a shared dependency changes the behavior of an entire computer system. Humans are a lot messier than that.

So the beauty of brainwashing/deprogramming is how you actually manage to substitute those axioms, even though they may actually lead them to disregard everything you say. That's like inception from the outside!