Confirming the video's point:
The Lamanites are supposedly the ancestors of today's Native Americans. When God punishes white people as he did the immoral Lamanites, they become vile, debauched savages--i.e., Indians. But all is not lost. If these unholy creatures return to God's ways and follow the Book of Mormon, they can become "pure and delightsome"--i.e., white--again.
Hence the Mormon effort to proselytize Indians throughout the Americas. These people were white until they stopped obeying God. Once they resume obeying God--as interepreted by Joseph Smith--they'll grow lighter until they look like white people again. Mormonism can save them from God's curse of being brown.
In other words, Mormonism is racist at its core. Nice.
For more on the subject, see Mormon Leaders Made a Mistake and The Indian-Mormon Connection.