The significance of the labeling of names that Mormon used is underscored by the children of Amulon (as representative of all the priests of Noah) who decided that they are no longer to be designated by the name of their fathers, but rather that they should be called “children of Nephi.” This was a symbolic move which declared their political affiliation as well as a rejection of their fathers’ actions.
Mormon uses this action to note that even though he has indicated that there was still a separation between Nephites and Zarahemlaites and that, for political purposes, they were all called under the name of Nephi. Thus, there are lineage connections and divisions, but the overall political allegiance is still defined as Nephite and Lamanite, or, us and them.