On the contrary, cultists are bright, idealistic, caring individuals. They get “hooked” because they believe they will be doing important work for the betterment of mankind. Nobody joins a cult; they join a cause!
Intelligent people also have needs, frustrations and disillusionment. It is more a matter of feelings than intelligence. If people always dealt at an intelligence level, we would not have the divorce rate we have, nor would anyone ever make mistakes. How often do we ignore what we know and act on what we feel?