Again, this message board is not about preaching beliefs, but rather discussing the behavior of groups and leaders.
How do they abuse authority to exploit and do damage to people?
Do they exploit people financially, or damage their relationships?
Do they expect and exploit free labor?
This can be seen objectively through their actions in the way they run a group and influence people.
This research paper by a sociologist explains coercive persuasion techniques often used by destructive cults to manipulate people.
The key factors that distinguish coercive persuasion from other training and socialization schemes are:
The reliance on intense interpersonal and psychological attack to destabilize an individual's sense of self to promote compliance
The use of an organized peer group
Applying interpersonal pressure to promote conformity
The manipulation of the totality of the person's social environment to stabilize behavior once modified
Another excellent resource to understand cultic manipulation is the book "Thought Reform and the Psychology of Totalism" by psychiatrist Robert Jay Lifton.
In this chapter Lifton explains how by controlling the environment and information groups can psychologically control people.
This is the "Recovery" subsection of the Ross Institute Internet Archives. This subsection contains articles about recovery from destructive cults. It explains the fear, emotional paralysis and other debilitating results that may occur through cult involvement and how people can recover from those effects.