I think new converts need something like this in their lives for some reason or another. Maybe they need the comfort of a high control group. It is like they are mentally deficient in someway, not to be construed as mentally challenged, and they have found what they need mentally to cope.
I have seen it to younger people accepting the WTBTS doctrine and all of this other info is out there to preview before making the jump.
To some up, I think it just fills a need for some poeple and so they submit to it.
M