If you want to see effective brainwashing, you need to look for instances where Pavlovian conditioning and enhanced states of suggestion (essentially “hypnosis”

If you want to see effective brainwashing, you need to look for instances where Pavlovian conditioning and enhanced states of suggestion (essentially “hypnosis”, but think of the clinical definition, rather than stage performance tropes) are combined over the course of years in a way that self reinforces the thoughts to be held. Works best when the person is offered something that they think they need (validation, community, sexual release, security) and if the person is already or can be isolated from interfering peers. Basically look at what cults do, though it doesn’t even need a machiavellian mastermind involved, people can and will accomplish the same largely by their own initiative. This is what happens when you get online communities radicalizing themselves.