The word "cult" is such a loaded term that it does not have much meaning. I attended once several years ago a convention of the American Family Foundation, a group that provides information about cults. The convention seemed to be mostly made up of psychologists. The speaker was giving a lecture on what is a cult. I still have my notes from it, but they aren't handy right now. He spoke about the development of a cult, and its relation to denomination, church, sect. Being a sociologist, he gave a long definition of "cult" which was more neutral than others I have seen. He considered early Christianity to be a cult.
I was in the audience and asked the question, "Is there such a thing as a good cult?" One prominent cult expert, who was sitting in the row in front of me, answered, No, there is not. A cult is about control. However, the speaker answered, Yes, there can be a good cult. He said that it is like a baby with a handgrenade, the baby is dangerous, but not necessarily destructive. A group that has an authoritarian leader is dangerous, but not necessarily destructive. The speaker cited Jesus, whom he considered a good person, yet he said Jesus, using the speaker's definition of a cult, was a cult leader. If Jesus had asked Peter to go kill someone, Peter would likely have done it, but Jesus was a good person, and would not have asked Peter to do that. So I could see that there was disagreement among the cult experts.
Then the head of the foundation answered. He said that some wanted to limit the word "cult" to groups that are destructive, or use the word the phrase "destructive cult", or instead of "cult", use the phrase "new religious movement". The head of the foundation also gave a lecture on the nature of cults. His explanation was quite complex. He saw the concept of "cult" as being not black or white, but on a spectrum. He illustrated his conception by using overlapping circles, such as in a Venn diagram. There are cults, new religious movements, abusive groups, and harmful practices. But these circles overlap. He said that there were people that had determined that the group they belonged to was a cult, but decided to stay in it anyway, and manage somehow within it, perhaps by lessening their involvement. Again, I made notes of this, but don't have it right now.
Some use the word "cult" in a neutral sense. However, it has such a negative connotation now, that it has little usefulness, except to express one's disdain for a religious group. No doubt there are bad religious groups, that don't deserve to exist, and that every person should flee from or leave. But most religions have a mixture of good and bad, just like the individuals in them. The concept of "cult" oversimplifies religion.
Religion by its nature is subject to this mixture because it attempts to mediate the divine through imperfect humanity, and one can confuse the divine with the human, and the human with the divine. The stained-glass window is a work of beauty, but it is nevertheless man-made, and its beauty can best be seen when the light shines through it. Its beauty can be so dazzling that one could mistakenly think that the window itself is producing the light, rather than the heavenly sun beyond it, and become disappointed when night falls and the window becomes dark.
One should be wary of religions claiming to be "the one true church", and denouncing all others as "Babylon". But anti-cultists are just as capable of being manipulative, misleading, lying, and have a hidden agenda as the cults they condemn. Their claims need to be critically examined as well.