The manner in which these organizations go about their business, the way they achieve their goals, and the way they treat members and society are arguably more important considerations than the actual goals of the organization and its leaders. Cults are typically an exercise in grandiose egotism in which the cult founder tries to convince his flock, and the world, that he is more than human and that his value system is the solution for all earthly problems. Such organizations can be eligible for tax-exempt status from the US Government, they collect and demand a rich harvest of donations from members, and often create an army of conscripts to further the recruiting and business interests of the founder. There are many. Cult members often lose access to health care, which can be seen as dangerous, evil, or as evidence that cult cures don't work.
People can and do die by participating in cults.
If a person is denied food and medical treatment even simple problems can become fatal. Children or women in a cult may find themselves in forced sexual or marriage relationships with the founder or his trusted officers. The pressure to dedicate time and donate money can be so intense that your college money may end up funding a cult instead of an education. Forced starvation and malnutrition, sleep deprivation, loss of personal freedoms and identity, and the emotional and spiritual assaults that cults leverage to achieve their goals can leave a person with deep emotional and financial scars that will not soon fade. In general, your life is probably not at risk and such a thing would represent a rare and extreme situation.