This is part of a well-established pattern of censorship by Church employees who follow the M2C intellectuals. Although these materials are approved by Church leaders, the materials are prepared by staff who are trusted to be accurate and truthful when they write these manuals.
I don't believe any Church leaders would knowingly approve of the deliberate censorship of teachings of the prophets who preceded them, especially when the censorship is driven by the desire to promote M2C.
Look at the comparison below to see how the employees who wrote this manual changed Brigham Young's clear teachings to accommodate M2C. The blue in the right column is the original. The red in the left column is the work of the censors.
Original talk in Journal of Discourses
When Joseph first received the knowledge of the plates that were in the hill Cumorah, he did not then receive the keys of the Aaronic Priesthood, he merely received the knowledge that the plates were there, and that the Lord would bring them forth. … He received the knowledge that [early inhabitants of the Americas] were once in possession of the Gospel, and from that time he went on, step by step, until he obtained the plates, and the Urim and Thummim and had power to translate them.
When Joseph first received the knowledge of the plates that were in the hill Cumorah, he did not then receive the keys of the Aaronic Priesthood, he merely received the knowledge that the plates were there, and that the Lord would bring them forth, and that they contained the history of the aborigines of this country. He received the knowledge that they were once in possession of the Gospel, and from that time he went on, step by step, until he obtained the plates, and the Urim and Thummim and had power to translate them.
Notice: the original phrase "aborigines of this country" was censored and replaced with "early inhabitants of the Americas."
The revisionist historians in the Church History Department have adopted the term "Americas" to replace the original language (this country) wherever they can, such as in the commentary in the Joseph Smith Papers. If you search the Joseph Smith Papers website, you'll see that the term "Americas" appears only in the commentary, not in any of the original sources.
The reason is that M2C intellectuals and their followers (including teachers at BYU and CES) teach that the hill Cumorah is in southern Mexico. They teach that the prophets are wrong about Cumorah in New York.
Censoring the teachings of the prophets is essential for the success of M2C.
Censorship is bad enough, but in cases such as this Brigham Young manual, the M2C employees go so far as to change the teachings of the prophets.
I think this is a breach of trust because future generations who rely on these doctored manuals will never know what the prophets have actually taught.
Where did Brigham Young learn that Joseph received the knowledge that the plates contained the history of the aboriginal inhabitants of this country?
Obviously, he could have heard it directly from Joseph Smith.
Perhaps he read and believed the Wentworth letter, in which Joseph wrote this:
I was informed also concerning the aboriginal inhabitants of this country, and shown who they were...
The same sentence was contained in a follow-up article, published in 1844.
Or perhaps Brigham Young also read and believed Letter VII, which explains that on his first visit to Joseph Smith, Moroni
then proceeded and gave a general account of the promises made to the fathers, and also gave a history of the aborigenes of this country, and said they were literal descendants of Abraham.
Letter VII was first published in 1835 and republished in most Church periodicals during Joseph Smith's lifetime. You can read it in Joseph's personal journal here:
M2C intellectuals and their followers reject Letter VII, the Wentworth letter, and every other source that affirms the New York Cumorah and teaches that the Lamanites were the ancestors of the aboriginal inhabitants of the United States, circa 1835-1842.
The M2C intellectuals and their followers teach that Joseph didn't know much about the Book of Mormon. They claim he was an ignorant speculator who misled the Church, because they, the M2C intellectuals, have the training and expertise to know that Cumorah is actually in southern Mexico and that the events in the Book of Mormon took place in Mesoamerica.
These misleading manuals have been translated into dozens of languages. Consequently, not only future generations but members of the Church who can't read English will never know what the prophets have actually taught.
Instead, they have to accept the work of the M2C intellectuals and revisionist Church historians.
Here is the link to the manual:
Here is the link to the Journal of Discourses:
*M2C is the acronym for the Mesoamerican/two-Cumorahs theory, which teaches that the prophets are wrong about the New York Cumorah because the "real" hill Cumorah is in southern Mexico.