In my experience, all of these new agey type culty groups have their own demographic audience.
So Byron Katie is appealing to a certain segment of the population, from their materials, it appears to be mostly women, and women who are in a lot of pain, and women who MAY have a bit of the "disease too please" and be "too nice", and who are also HIGHLY SUGGESTIBLE TO HYPNOSIS an
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"Cults," Sects, and "New Religious Movements"