People who join cults often do so as an attempt to meet a psychological need. This can be anything from a need to feel wanted, a need to feel loved, a need to fee special, a need to feel set apart by virtue of a secret knowledge.
Some of the very first cults were knowledge cults. The whole gamut of gnostic sects/cults from the pagan Nasoraeans to Manichaeism, to Redmon’s Celestine Prophecy have attracted their followers. People join these to find feelings of speciality in the ‘secret’ knowledge they gain. In some sense, Scientology can be considered a gnostic cult because of the special knowledge that comes from advancing in the cult.
Sex cults have long been popular as well. Springing from the ancient cults of Inanna and her new names throughout history (Isis, Venus, Aphrodite, Ishtar, Astarte, Freya, Xochiquetzal and others. Sex cults continue through to this day but their aspects have changed. Whereas in older days they were more of a type of love/lust cult with men and women as equals from there it moved to the role of women being made to priestesses/temple prostitutes in such cults as Ba’al, Enki and others to the modern sex cult which moves far away from such “loose morals” to a darker side of the sex cult where women become chattel. These newer cults usually practice varying forms of abuse either in the sense that the priest/leader can (and in many cases must) have sex with all/most of the women or else they use polygyny to have many women “married” to one man who then is free to have sex with them all but they are unable to have sex with anyone but their husband.
While I can understand the draw of knowledge cults to individuals with psychological issues relating to power and belonging and I can understand the draw of sex cults to men with repressed inadequacy issues I can only see the draw of modern sex cults to women as manifestations of their inner feelings of unworthiness. This is probably why there is much intermarriage in these cults as their daughters are raised to feel that they cannot be complete or even able to reach heaven unless they are married to a male cult member.