There is no such thing as black magic, you don't need that, just people who know how to manipulate others, just like every cult. I am pretty sure there are in actuality a few people running the show, the rest are idiots who are just as, or even more manipulated than the rank and file. If Lett is anything more than a stooge, he deserves an award for acting.
It may make you feel better to think this is some other worldly machination, but really it is quite easy to fool people who want to be fooled, or who gain something by buying into a concept. People who became JWs were concerned by world events and and/or wanted to think they had special knowledge. Everything in their playbook is cult 101, nothing mysterious, doesn't require anything other than a will to use others for their own ends. Who knows what that end is, but it's likely quite banal, like financial security or a need to control others.
Just a$$holes in the end.