Logo,
This is not true in the process of defining something you may come across a property which can be used in an exclusionary way. In this case the Mormon penchant for polytheism (Where by they themselves can become a God) excludes them from Christianity. The Fact they limit Gods power by saying there are other Gods of other planets also excludes them..
points of Heresy are rather easy to spot when they are that bad..
Even if I did agree with your characterization of our beliefs (which I most certainly do not), it misses the point.
You cannot reasonably call something a heresy unless you have some definition of orthodoxy.
Likewise, you cannot say Mormons are not Christians unless you can say what beliefs, practices, or characteristics define a Christian. How do you define Christian?