cult (noun): A religion or religious sect generally considered to be extremist or false, with its followers often living in an unconventional manner under the guidance of an authoritarian, charismatic leader -- American Heritage Dictionary
Without the "generally considered to be extremist or false" it would be quite hard to even identify a cult. It's mostly used as way to slur a disfavored group. It's an element of a Russell conjugation, like I am part of a spiritual awakening, you belong to a religious sect, they are in a mind-control cult.I was raised as a Jew. I consider that to be a cult, if one of the milder religious ones. My peewee football team was a cult. I belonged to a cultic political party, and worked for a startup that closely met the definition.
So getting someone to leave a cult is going to be the same as getting them to forsake any other community, just with the added coercion of social acceptability. There's no magic, no brain unwashing, it's the same kind of persuasion used to sell a vacuum cleaner.