And that's why, partially, people like you buy hair-brained ideas like Moroni in Utah and are impressed by pop speculators like Ainsworth.
Brigham Young dedicates site of Manti Temple - LDS.org:
"Brigham Young announced the (Manti) temple site 25 June 1875 and dedicated the site on 25 April 1877. Earlier that same morning, he had taken Warren S. Snow with him to the southeast corner of the temple site and told him, “Here is the spot where the Prophet Moroni stood and dedicated this piece of land for a Temple site, and that is the reason why the location is made here, and we can’t move it from this spot.”
LDS.org - Ensign Article - The Manti Temple
Some references for Moroni also dedicating the St. George Utah Temple site:
"The temple sites credited to Moroni were at St. George, Utah and Manti, Utah. Brigham Young met with the leaders of the Church in St. George, Utah to announce the building of a Temple. David Henry Cannon Jr., a member of the St. George Temple Presidency, was in attendance when President BrighamYoung said of the St. George Temple site,
This spot was dedicated by the Nephites. They could not build it [the Temple] but we can and will build it for them.
Those present at the meeting believed Brigham was referring to Moroni as one of those Nephites who dedicated the site at St. George. President Cannon reported that "many rumors" were circulating that Brigham Young had said that "Moroni, the Nephite-General had actually dedicated the site where the Temple now stands."
Brigham Young's statement that "Nephites" dedicated the site for the St. George Temple is consistent with Warren S. Snow's testimony that Brigham Young said that Moroni, a Nephite had dedicated the site for the Manti Temple...
"Moroni had the great privilege, as he walked across this American Continent, of finding a place and designating the place where the St. George temple was to be built. He also designated where the Manti Temple was to be. And it’s been written that he designated Kirtland and Nauvoo and probably others. Moroni appeared to the Prophet Joseph Smith 22 different times during the life of the Prophet Joseph that we know of." Elder Glenn L Rudd 2003
The Angel Moroni
"The site for the temple at St. George was swampy, but Brigham Young insisted that it be built there because the spot had been dedicated by ancient Book of Mormon prophets (statement by David H. Cannon, Jr., Oct. 14, 1942, quoted in Kirk M. Curtis, "History of the St. George Temple," Master's thesis, Brigham Young University, 1964, pp. 24-25)."
History of Mormon Temples