The Lamanite reaction to the presence of the Gadianton robbers is different from the one that we saw among the Nephites. The Lamanites make every attempt to rid themselves of the robbers, but the Nephites did not. What made the difference?
For the Nephites, the Gadiantons represented a dissenting political/social movement within Nephite society. They were not completely foreign, but were part of the Nephite world. In contrast, the Gadiantons appear to be usurpers among the Lamanites. They did not have the same base of operation, and in Mesoamerican terms, would not have had the kin/clan structures to support them. Therefore they would be more readily seen as foreign among the Lamanites, and therefore a danger to the majority, where in the Nephite lands they were becoming the majority.