We've already covered two important issues of distinction between Mormons and Christians. The first was the Authority of Sacred Texts, The second - the non-negotiable doctrine of man's depravity/original sin.
Of all the reasons Mormons have pleaded with Christians to "please call us Christians too" has been the idea that "saying we love 'Jesus Christ' " should in fact be enough. This thinking isolated as its own argument is utterly ridiculous - and under such would have made the Branch Davidians or the Jim Jones followers "Christians" as well.
The issue of "loving Jesus Christ" depends fully upon WHO Jesus Christ is. And the Jesus Christ of Mormonism is a different Jesus - one of Joseph Smith's imagination - than is the Jesus of the Bible.
Let's examine some of the differences.
Biblical Christians believe that Jesus Christ, God the Son, existed eternally. Jesus Christ always was, and always will be. He existed before Abraham, and before Adam. The biblical term of "firstborn over all creation" in the biblical text is the word prototokos which means "preeminent one, or first in rank." Christians also believe that Jesus Christ is the "only begotten" Son.
Mormons believe their Jesus was "born of heavenly parents." This belief stems from another doctrinal issue the belief that the Mormon God the Father had many spirit wives and that Jesus was conceived in the sexual union with one of these wives. Thus the Mormon Jesus is born of a procreative act. Thusly they also hold that there were many other "spirit children" of the Mormon God the Father.
Lastly Christians clearly believe the biblical text when it ascribes attributes to Lucifer, who became Satan after is fall - as a created angel - a cherub. Mormons believe that Lucifer was actually a spirit brother to the Mormon Jesus.
Kirby Anderson states it this way:
Mormonism teaches that Jesus and Lucifer were involved in planning mankind's eternal destiny. In order to attain godhood like our heavenly parents, the spirit children needed to leave the presence of their heavenly Father, inhabit a physical body, and live a worthy life. Elohim knew that mankind would sin and thus require a savior to pay for sin and show us how to return to our heavenly father. At the heavenly council, Jesus and Lucifer proposed their plans. Lucifer offered to go to earth and be the savior but he wanted to force everyone to be saved and do everything himself. Jesus desired to give man the freedom of choice. The Father chose Jesus' plan. Angered by the decision, Lucifer persuaded one third of the spirit children to rebel and a war in heaven took place between Satan's forces and Jesus and His followers. Lucifer was defeated, cast out of heaven, and denied the right to inhabit mortal bodies.
This makes for some fascinating imaginative story telling...
But to Christians its blatant apostate heresy.
No one on this forum has said that Mormons must change their beliefs. They are much allowed as we all are to hold those beliefs in their hearts that the cherish most. But Biblical Christians do not worship the Mormon Jesus, and Mormons do not worship the Biblical Jesus. And it is heresy to Christianity to say otherwise.
And there is not getting past this divide. Thus Mormons place themselves outside the circle of Christianity and firmly inside the circle of Mormonism.