Every person under the sun is weak to the effects of an effective brainwash. In these cases, they're especially susceptible, because they're open to it.
Auditing is the process through which they clear "engrams" from the subconscious. It is basically untrained hypnosis, and dangerous. They say it's not hypnosis, but a state of high suggestibility. Same thing to me.
It is through auditing that they become better Scientologists. In this process, however, the brainwash sets in. Eventually, subjects believe that the way of the CoS is the *right* way of doing things. It is a misguided but honorable goal. I've met many Scientologists, many of them are very smart and very capable. My brother in law is hilarious and a great friend. He's not weird by any means. He wants to do it to become a better person. Any attempt to steer him away from it gets shut down rather quickly.
The CoS is full of mostly well-intentioned people that got caught up in a dangerous web of lies (and economic loss). They have been psychologically programmed to do things that we find offensive.
It is very interesting to see the defense mechanisms that church policies have. Almost every rule I've heard of can be easily tied to preventing the Scientologist from realizing the harm he's caused himself: psychiatric treatment (especially medication), the "internal law", keeping "suppressive personalities" away, etc.
My brother in law is quite reasonable in his unreasonableness. He understands we disagree so we hardly touch the subject anymore, and he is open to discussion, but is NOT open to finding a middle ground. Any attempts to do so are seen with skepticism.
He's told me numerous time that the "space opera" that you can read about in Wikipedia is just made up by the press, I wonder what's going to happen when he hits OT3 and they serve it to him on a hot dish of shit.