As you know that book has no authority to Christians. You also know that we believe in a different Jesus ,that was affirmed by your own prophet. That could be why we would disagree on that .
"In bearing testimony of Jesus Christ, President Hinckley spoke of those outside the Church who say Latter-day Saints 'do not believe in the traditional Christ.' 'No, I don't. The traditional Christ of whom they speak is not the Christ of whom I speak. For the Christ of whom I speak has been revealed in this the Dispensation of the Fulness of Times. He together with His Father, appeared to the boy Joseph Smith in the year 1820, and when Joseph left the grove that day, he knew more of the nature of God than all the learned ministers of the gospel of the ages.'" (LDS Church News Week ending June 20, 1998, p.7 )
As the Holy Spirit bears witness, and as I bear witness, that book (the Doctrine and Covenants) contains the words of Jesus Christ in the first person, spoken to His modern-day apostle, written down and canonized by His Restored Church, whose members are Christians.
If that does not have authority with some other Christians, what can I say? It certainly should.