Mormonism is NOT Christian.
A cult of Christianity is a group of people, which claiming to be Christian, embraces a particular doctrinal system taught by an individual leader, group of leaders, or organization, Source: Alan Gomes, Cult: A Theological Definition, excerpt from "Unmasking The Cults"
Certain Christian doctrines constitute the core of the faith. Central doctrines include the Trinity, the deity of Christ, the bodily resurrection, the atoning work of Christ on the cross, and salvation by grace through faith.
These doctrines so comprise the essence of the Christian faith that to remove any of them is to make the belief system non-Christian. These are not mormon beliefs or doctrine.
Real weird that faith in the actual Christ is not cited as a factor that matters. But that would throw off a lot of religious folks.