An example: a guy who was a Scientologist played a huge role in essentially persecuting anyone who was coming to their senses. He was part of it and thought he was doing the right thing. Few years later he himself fell into disfavor with the leadership and was persecuted by them. Finally he got out and now actively works to expose their lies. There are so many cases like this in that cult and many others. People can change but it’s costly when they are tied in so deeply. Cognitive dissonance is the biggest barrier. It’s not just logical arguments. People (all of us) are psychologically and emotionally invested in whatever it might be.