The word "Christian" is found only three times in the Bible, twice in derogatory usage and once neutral (Felix's statement to Paul "Almost thou persuadest me to become a Christian.")
"Christian" was a term given to the "cult" that followed Jesus Christ by enemies of the faith.
However, scores of times the disciples of Christ are called "Saints" among themselves. It is the name they had for themselves.
So in a narrow sense, you're right. We're not "Christians," we're Saints, which is the correct term for those who believe in the true Christ.
Further, although we have deep respect for all religious faiths, we firmly believe that all other sects purporting to be Christian have only a portion of the truth, and are the result of apostasy over a millenium and a half ago.
The Church of Jesus Christ of Latter-Day Saints is a restoration of the ORIGINAL gospel, to correct the grievous errors that crept in over the centuries, and which resulted in the great variety of beliefs among the so-called "Christian" sects.
And you might want to dismiss that as irrelevant. Upon which I recommend you go to the RELIGION forum on FR, and take note of the HUGE number of threads arguing doctrine among the various sects: Protestant against RC and RC against Eastern Orthodox, etc., ad nauseum.
There are over 700 different Christian sects on earth. Not all can be correct.
But one Church is the true and living Church of Jesus Christ. It is the one that bears His name, with the further distinction that it is the Church established in the LATTER days (as opposed to ancient times where it also existed).
You singlehandedly destroyed all their efforts, demanding that the LDS church is not Christian while impugning every Christian denomination. The leaders of your faith are probably quite unhappy with your efforts.
True, there are many disagreements among the Christian denominations. However, if you examine them, what you'll find is that they disagree on such things as the proper organization of the Church (bishops or not, the authority of the Pope, etc.), whether specific behaviors (drinking, dancing, card playing) are sinful, whether Saturday or Sunday is the proper day for the Sabbath, the proper order for worship, or other such differences. There is little disagreement on the basic doctrines of the nature of the Trinity, or whether humans can ascend to divinity, etc. And it is in just such basics that the LDS differs from them all.
You are certainly free to believe that all Christian sects are in error, and that you yourselves are the one true Christian Church. But don't expect to be accepted and called Christian by Christians, as you don't meet the generally accepted definitions.