If you don't like a group, call them a cult. Some totally deserve it, such as People's Temple, Aum Shinrikyo, and Heaven's Gate. Was the Manson family religious enough to count as a cult?
Critics accuse cults of using mind control or brain washing. Isolation, sleep deprivation, etc. make persons more vulnerable to manipulation. Hard to resist the love bomb.
The stereotypical cult leader gathers followers through charisma and indulges in corrupt practices.
Deceptive recruitment hides the true doctrine of the cult from the recruits until after they have made an emotional commitment. Initiates may excuse this behavior because "The recruit is not ready for that knowledge." And it is true that you don't learn trigonometry before you learn geometry. But something is different... You can study trigonometry without understanding geometry first, but you will struggle and fail, or struggle and reinvent geometry and succeed with difficulty. Most importantly, there is no reason to hide the principles of trigonometry from people who studying geometry. So this obfuscation looks suspicious to me.
Cult members feel deep loyalty and motivation and willingly depart from social conventions. They often feel a profound sense of purpose and belonging. If their loyalty is born of the manipulative influence of the leader, and they embrace their beliefs uncritically, then their loyalty and motivation is misplaced, their belonging is a sham, their purpose is warped.
Normal, intelligent persons are vulnerable to recruitment by cults. One of the greatest strengths of advertising is that few people seriously consider the possibility of their vulnerability to manipulation.
I think everyone from a young age should study how to recognize and resist cult recruitment techniques and other forms of manipulation.
Can persons manipulate themselves using similar techniques, act as their own guru? Or will self-manipulation breed self-deception? Is it possible to form cohesive groups with intense loyalty and motivation that have no charismatic leader or stultifying dogma? Or is that the glue that holds a cult together, and ending the leader worshiping dogmatism will inevitably end the cult?
Group dynamics make people act strange. Haidt believes that our "groupishness" allows us to cooperate. This impulse gives fuel to civil society, the part of our lives that requires neither government coercion nor market incentives. In the age of the Internet, civil society can accomplish a lot.