My God, my God, why hast thou forsaken me?

[Angrboda]

"Christians, it is needless to say, utterly detest each other. They slander each other constantly with the vilest forms of abuse and cannot come to any sort of agreement in their teachings. Each sect brands its own, fills the head of its own with deceitful nonsense, and makes perfect little pigs of those it wins over to its side." -- Celsus (2nd century C.E.)

As I said before, Christianity is simply whatever it is that Christians believe.  Your absurd notion that there is some "correct" party line dividing Christians from pretenders to Christianity is just some partisan bullshit that you believe.  It doesn't have an ounce of logical weight.

That make no sense whatsoever. Christianity at its base makes a certain set of metaphysical, natural and supernatural truth claims. The nature of many basic Christian claims is exclusive. By definition if an ideology is exclusive, it claims that those ideological beliefs that are in conflict with it are false.  Therefore it appears there is at least a basic list of truth claims you must agree to or you are excluded. Where do we get ANY of the truth claims from? The NT. Therefore if your belief is in obvious conflict with the NT, then it follows that belief is not Christian. 

Another proof, say in 1000 years, there are no Christians. Would the ideology labeled Christianity cease to exist? No, it could be rediscovered if someone were to ready the NT. What if a scholar compared the NT with the The Book of Mormon? Would they be able to list the precepts of one against the other and make a comparison? What would the columns be labeled? If they conflicted, can you logically claim they are all Christian? 

For example, Mormons are polytheistic. That is direct conflict with any number of foundational precepts that Christianity claims. Mormons are not Christians.

You would have been more honest if you would have said "my Christianity" in the above instead of just "Christianity." You claim that Mormons are polytheistic. They don't see it that way. It's a matter of subjective opinion. Jews and Muslims see you as polytheist. You see it differently. Neither claim is based on an actual objective fact. Christianity is by its nature pluralistic in fact, but exclusive in belief. That doesn't change the fact that what one Christian or another excludes from Christianity is based on subjective opinion, and so enjoys no privilege over what any other person who claims to be Christian believes. Are you a Christian if you don't believe in the book of Mormon? It is a matter of opinion. Does the Gospel of Peter belong in the bible? Again, opinion. Does the Gospel of John belong in the bible? Again, opinion. All you've got is a bunch of subjective opinions about what does and does not make someone a Christian. Historically, the determinant of what was Christianity came down to violent suppression of minority opinions and consensus of those in power. Neither gets you to an objective fact of the matter. One might argue that belief in some kind of Christ is necessary, but since Mormons fit that bill, you're simply out to lunch here. I recognize that you've drunk the koolaid which outlines your specific beliefs and that you feel that anyone who disagrees with you is not Christian, but ultimately that is nothing more than your subjective opinion on the matter. Your opinion doesn't mean dick when it comes to settling just what Christianity is, exclusive or not. It's just your opinion, nothing more. Anybody else who happens to believe in Jesus Christ of some form and calls themselves Christian has as much basis for saying what is and is not a Christian as you do, which is to say, not much. Christianity is a social movement based around beliefs about Jesus Christ. Anyone that fits that description is therefore a Christian, in spite of the perennial bickering over who does and who does not belong in the club. Such disputes aren't based on objective facts and so they are worth dick squat in resolving the question. The best you can come up with reduce to appeals to popularity or might makes right arguments, neither of which is a rational basis for determining who is and is not a Christian.