Did you know that a cult is not necessarily a religious denomination? The hallmark of any cult is control and domination by the leaders over the members. A cult controls what the members read, what they can do - even how they must think. A cult prevents the members from association with non-cult people - even their own family. A cult will punish any member who disobeys the leaders. Cults are all about manipulation and control.
Destructive mind control is not just used by some religious organizations - it also applies to Human Trafficking and Terrorism. The point is that ANY organization that seeks to control how people think, what they can read and how they should act is a cult. Not necessarily anything to do with religious beliefs.
The simplest way to test whether an organization is a cult is to try to leave them. See what happens to Scientology members who try to leave - they are punished. See what happens to Amish teenagers when they leave - they are shunned. What would happen to a baptized Witness if they disagreed with the organization and the elders, questioned the leaders and wanted to leave? They would be branded as an apostate and subsequently disfellowshipped. They would be shunned by even their own flesh and blood.
As for terrorist organizations that exploit people politically, or organizations that are out simply for monetary gain, anyone who tries to leave could loose their life.
Take your pick - the world is full of cults that manipulate, control and destroy the lives of their members. The thing is, nobody ever knowingly joins a cult. Trouble is, once they have their hooks into you, it can become very difficult to leave.