A high-demand religion I would guess would be some sort of fringe cult? If so within every one of the modern religions/ideologies there are similar fringe cults that are hate-filled with dogma for everyone else not in line with their ideology. Some feminists hate all men, some communists hate all Capitalists and everything must be done according to Communist dogma even when it's clear that it does not work... etc. The mainstream is usually not what the experience of a fringe cult within that ideology is.
> high-demand religion I would guess would be some sort of fringe cult?
Typically less fringe than you may think. Quoting "Visualizing the Transition Out of High-Demand Religions":
> Subjects include disaffiliated Mormons, Jehovah’s Witnesses, and Fundamentalist Protestants
Typically these groups express many of the same characteristics as "mainstream" religions due to their age, and share the same elements driving religious decline.
