Howdy
I used to be in a christian cult (jehovah's witnesses)
When i was in, i believed in it so hard. I used to go door to door knocking, spent over 30 hours a month just doing that.
I think that fear is very powerful. I was raised to believe that some day soon, the government was going to crack down on religion and we (JWs) would be the last religion standing and when the police showed up to kick our doors in, we would have to stay faithful even if it meant our lives.
Next, they said, armageddon would come and everyone who wasnt a JW would die, our reward for our faith would be being resurrected or making it through the "great tribulation" , those who had died would be resurrected.
All would have the promise of life on earth for eternity, not heaven, not hell, just earth that we would have to clean up, the pollution, the trash, the 7+billion dead bodies that would be lying everywhere.
It was the fear of being destroyed forever along with the promise that if we were faithful enough, we would live forever. Two very important extremes.
There are so many people who make it out of there, people like me, many who have committed suicide because of shunning and depression. Many, if not most, have some form of PTSD or trauma. There are thousands of us who have made it out, more to follow. We all support eachother through facebook groups now.
Back to the question, why are people still brainwashed?
They have a hope, and they have a fear of the opposite of that hope. Religious people live very rigidly, and they live in extremes. Theres one side, and theres another. Left, right. Up, down. Evil, good.
Very rarely will you find a middle ground.
And you can't tell them to wake up, because it only enforces their persecution complex.
All you can do is what i do with my grandmother; love her from a distance and know that she'll never see me as anything but less than. And be okay with that and be thankful that she hasnt completely shunned me out of her life; because there is enough love for me there for her, that she would be partially willing to give up her chance at living forever just because she is talking to me, which she is not supposed to do, according to cult standards.
Love them. Simply. Love them until they start questioning why a bad person like you is being so kind. Thats when the first questions start, hopefully. And then critical thinking will follow, and then eventually they'll figure it out for themselves.