Can you spot the difference in Christ's discourse on "those in Moses' seat"?

KJV:
Then spake Jesus to the multitude, and to his disciples, saying, The scribes and the Pharisees sit in Moses’ seat: All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not. For they bind heavy burdens and grievous to be borne, and lay them on men’s shoulders; but they themselves will not move them with one of their fingers. (Matthew 23:1-4)

Inspired Version:
Then spake Jesus to the multitude, and to his disciples, saying, The Scribes and the Pharisees sit in Moses' seat. All, therefore, whatsoever they bid you observe, they will make you observe and do; for they are ministers of the law, and they make themselves your judges. But do not ye after their works; for they say, and do not. For they bind heavy burdens and lay on men's shoulders, and they are grievous to be borne; but they will not move them with one of their fingers. (Matthew 23:1-4)

In the first, its as if the Lord is giving us a command to observe all these leader's whims.  In the inspired version, he does not.

Nephi's vision of the Bible:
"Wherefore, thou seest that after the book hath gone forth through the hands of the great and abominable church, that there are many plain and precious things taken away from the book, which is the book of the Lamb of God. And after these plain and precious things were taken away it goeth forth unto all the nations of the Gentiles; and after it goeth forth unto all the nations of the Gentiles, yea, even across the many waters which thou hast seen with the Gentiles which have gone forth out of captivity, thou seest—because of the many plain and precious things which have been taken out of the book, which were plain unto the understanding of the children of men, according to the plainness which is in the Lamb of God—because of these things which are taken away out of the gospel of the Lamb, an exceedingly great many do stumble, yea, insomuch that Satan hath great power over them." (1 Nephi 13:28-29)

Why does the Inspired Version continue not to be used as the official translation of the bible in the LDS Church? This is one of the most significant contributions Joseph made in his calling from heaven, but we only use excerpts, hidden away in with the index, and topical guide.