The formal term for this fallacy is "appeal to authority," and it is among the most common fallacies you see in the citation cartel. Anyone interested can unpack the arguments made by Ferguson and Sperry; I find appeals to authority not worth the time and effort. Note that this fallacy is a different argument than an appeal to authority based on special credibility, such as a witness (which is why we publish the testimony of Joseph Smith and the 3 and 8 witnesses in every edition of the text). The appeal to authority fallacy applies when the cited authority has no more unique knowledge or expertise than anyone else. Any member of the Church can assess the same evidence that Ferguson and Sperry did and make up his/her own mind. There is zero reason to defer to them (or any other member of the citation cartel) on this issue.
Here's another way to put it. I invite every member of the Church to choose between these. Explicit descriptions of Cumorah in New York: Joseph (1827) David Whitmer (1829) Oliver Cowdery (1830) Oliver Cowdery's Letter VII (1835), reprinted in Joseph's personal journal (1835), Orson Pratt (1840), the Gospel Reflector (1841), the Times and Seasons (1841), D&C 128 (1842), and the UK pamphlet (1844). Explicit description of Zarahemla in Guatemala: Anonymous article in the 1842 Times and Seasons, never mentioned or referred to again until the development of the two-Cumorah theory by scholars in the 1900s.
In 1981, Palmer identified 13 geographical conditions required for the Book of Mormon Hill Ramah/Cumorah: near eastern seacoast [the text specifies no distance between Ramah/Cumorah and the sea] near narrow neck of land [the text specifies no distance between Ramah/Cumorah and the narrow neck of land (and notice that the Nephites never mention the narrow neck of land; it is found only in Ether 10:20)] on a coastal plain and near other mountains and valleys one day's journey south of a large body of water an area of many rivers and waters presence of fountains water gives military advantage an escape route southward hill large enough to view hundreds of thousands of bodies [The text doesn't require this, but in fact, from the top of the Hill Cumorah, you can see the city of Rochester 20 miles away. Oliver Cowdery refers to tens of thousands, which is consistent with the text. Certainly the mile-wide valley west of Cumorah, which Oliver identified as the scene of the final battle, is plenty big to accommodate this number of dead.] hill must be a significant landmark [which is how Oliver described it] hill must be free standing so people can camp around it [as the New York hill is] in temperate climate with no cold or snow [complete fabrication, the product of the Mesoamerican lenses. Nothing in the text requires this. The climate is never described in the text, except it had "some seasons," which excludes Mesoamerica anyway. This common Mesoamerican argument is like saying the Apostle Paul could not have traveled in Turkey because he never mentions snow. Yet snow in Turkey is well known; I've been in a snowstorm in Turkey where Paul traveled.] in a volcanic zone susceptible to earthquakes[12] [another complete fabrication that defies the text. See my post on fun with volcanoes]