I've always thought of a cult as having a mind control component to it as exercised by their leaders. Also, it usually means that the real power is vested in one person.... not always but usually as was the case with say Jim Jones. This is different than true Christianity which vests its power in Jesus Christ. Regardless of whether Mormonism fits a particular definition of cult is probably not worth exploring..... it is already a false religion and that is all that matters as far as what one needs to know.
Mormons believe this about Christ ....
..That Lucifer, the son of the morning, is our elder brother and the brother of Jesus Christ.
(Apostle B. McConkie Mormon doctrine p.163-164)
...Jesus, our elder brother, was begotten in the flesh by the same character (satan) that was in the garden of Eden, and who is our Father in Heaven,
(Journal of Discourses, Vol. 1, pp. 50-51).
in addition....” Jesus got married at Cana and had many wives Martha, Mary and others he also had many children
(J & D vol.1 345-346 vol.2 79-82 vol.4:259-260 the seer p.172)
This is NOT the Jesus of the Scriptures or even remotely so.
(Source: Let Us Reason)
There is a huge mind control compoenent in Mormonism, the use of fear, being discouraged from reading non LDS sources, shunning and many other things.
They even have long sessions of monotone voices repeating the same phrases over and over again presided over by their prophet whom they start off by thanking him and singing praises to their founder.
First weekend in October and April, watch BYU TV for just an hour or so (General conference) and you will see what I mean. When my husband and I were first married he wanted to watch General Conference with me, just to hear the MoTab choir. After 15 minutes he fell asleep because of the monotone, soothing voices and the tripe ‘talks’. It is a form of brainwashing.