MTSman, you are correct that it's crazy how "we" sane people can succumb to bat-shit crazy theories and beliefs, leaving the insane people out of the equation right now.
But you and I see pretty clearly how Scientology is bat-shit crazy. Those who have joined over the years did not have the benefits of hindsight and documentaries like GOING CLEAR.
Well, it's the same for Jehovah's Witnesses. People didn't know that what they were joining had bat-shit crazy theories. Recruitment is tougher in the 21st century with everyone googling everything, so we are on the dying edge of that. And being raised in bat-shit crazy stuff, even in the information age, many are re-wired to think that it is normal or that it is strange and different, but the normal stuff is bat-shit crazy.
Now, the insane factor. I am not the sane adult that joined. Things in my life were insane when I joined Jehovah's Witnesses. Same for people who may join Scientology or any dangerous mind-control cult. Cults pry on people going through huge stresses in their lives. Who's to say what's bat-shit crazy to someone whose whole life is bat-shit crazy?