It is a harsh realization when you wake up and find out that literally everything that you have been told as being most important was a lie.
Therefore the brain protects against that injurious state, by disconnecting from that reality, while holding onto the "love" that the cult members offer - acceptance, affirmation, etc.
This is adaption at work, arguably a good thing, i.e. a mechanism to protect someone as they are being abused.
Society has failed them, even as they feed that forward and now fail society.
We cannot change the past, only try to do as best we can to move into the future.