This might sound like a silly question or it might be a realistic one. Is A Course In Miracles a cult? Is ACIM a brainwashing device? One might ask alternatively, is the Bible the basis of cults? Perhaps some cults are based around the Bible, or perhaps some cults have been based around A Course In Miracles. The only time this answer might be yes is if there are individuals using A Course In Miracles in a coercive or unethical way. Probably most things can be used in a coersive or unethical way if one wants to use them in such a way. It might sometimes be legal to be unethical, but it does not make it right. There can be legal ways of acting unethically and there can be illegal ways of acting unethically. If ACIM is used unethically in a legal way, then perhaps that individual should simply be exposed or abandoned. However, if someone is using A Course In Miracles or any other spiritual or non-spiritual book to coerces and control others in a way that is illegal, then perhaps that is where the government should become involved, and those individuals should be held legally accountable for their actions.
In one sense, a cult is simply a pejorative term for “a new religious movement”. A Course In Miracles could perhaps be considered a form of new religious movement potentially, since it was reportedly scribed in the 1970’s. However, it can be a positive influence for many! It does not condemn anyone to hell.
So to call A Course In Miracles a cult or the basis of a cult is just as silly as calling any other potentially neutral or non-neutral idea or book the basis of a cult. It is really the actions of individuals that would determine whether or not ACIM or anything else has become negatively, illegally, and/or unethically utilized.