You say that, but . . . :

…Throughout the 1800’s, adherents cited the current existence of the “red sons of Israel” (i.e. Native American) as evidence of the authenticity of the The Book of Mormon.

Adherents saw Native Americans as part of God’s chosen people and they believed that preaching to them was part of the gathering of Israel which will precede the millennium. The church’s long history with Native Americans is tied to their beliefs about The Book of Mormon.  According to sociologist Marcie Goodman, historically Latter Day Saints held paternalistic beliefs about Native Americans needing help. Outreach to Native Americans became the first mission of Smith’s newly organized Church of Christ, as the purpose of The Book of Mormon was to recover the lost remnant of the ancient children of Israel (e.g. Native Americans).