I think you need to check your sources for study. This is the second time you have been factually incorrect that I have seen today.
According to Mormons, the Holy Ghost is a spirit, yes, but the child of God in EXACTLY the same way all the rest of us are His children. Jesus also was ‘only’ a spirit before He became the Only Begotten Son of God, through Mary, and gained a physical body. However, Jesus was still the second Person in the Godhead, “only” a spirit or not.
I would humbly request that, if you are going to accuse us of having ‘cultish beliefs,’ you at least get the beliefs right.
But let’s take a look at what a polytheist religion is, OK?
Polytheists believe in multiple gods, each god, generally, having responsibility for a specific area of life: one guards travelers, for instance, (Mercury…or Hermes)one guards the hearth and home, (like Hestia or Brigid) or another is in charge of animals, (say…Curnunnos) another specifically for athletes,(Hermes, again) yet others guard and guide those in specific careers: barbers,(Ninkamanna) beekeepers,(Melisseus) blacksmiths (Hephaestus)…and the believers pray to these deities for help in those areas. Miracles are attributed to them. Candles are lit at their altars, and offerings are made to them. Over all these minor deities is, generally, one major, over-riding deity who is in charge of all, though most of the time the believers choose to concentrate on the minor deities, having their figures in their homes and ‘contacting’ the major God through interaction with the minor ones.
Mormons have no such minor deities. We pray to one God, and one God only. Ever. That makes us, at most, henotheists.
Mind you, it doesn’t really matter what anybody else calls us, or what classification others put us in, if we happen to be RIGHT, does it?