Mormon condemns the people, not because of riches, but because of apostasy. Of course, there is likely a direct connection between accumulating wealth in Mesoamerica and these types of sins, but it is important to understand that righteousness is the key issue, not economics.
Culture: Mormon describes the Nephites’ quarrelings and contentions, both fairly nonspecific sins; but they indicate a schism in belief arising from significant differences of opinion. As always, dissent is the most dangerous of the internal threats to Nephite society. But Mormon then lists “plunderings” and “murderings.” Mosiah2 had denounced these identical sins, reminding the people that he had “labored with all the power and faculties which I have possessed, to teach you the commandments of God, and to establish peace throughout the land, that there should be no wars nor contentions, no stealing, nor plundering, nor murdering, nor any manner of iniquity” (Mosiah 29:14; emphasis mine).
When Alma and Amulek succeeded in launching a religious renewal, the priests they ordained “did preach against all lyings, and deceivings, and envyings, and strifes, and malice, and revilings, and stealing, robbing, plundering, murdering, committing adultery, and all manner of lasciviousness, crying that these things ought not so to be” (Alma 16:18; emphasis mine). These descriptions are never detailed, but I find it significant that plundering and murdering almost always appear together. In Mesoamerica, a reliable way of obtaining wealth was conquering other cities, which certainly would allow plundering. Perhaps “murdering” refers to these greed-motivated military attacks, which would not meet the gospel-sanctioned criteria of self-defense, or perhaps it referred to ritual human sacrifice.
The next pair of sins is “idolatry” and “whoredoms.” The first accusation of idolatry in the Book of Mormon is levied against the Lamanites (Enos 1:20), which suggests that the Lamanites had adopted local gods. The next idolater mentioned is King Noah, an apostate Nephite in the land of Lamanites who apparently adopted the Lamanite lifestyle (Mosiah 11:6).
“Idolatry” is also one of the sins of later Nephites, since Alma 1:32, lists a lengthy catalogue of offenses committed by non-church-men who “did indulge themselves in sorceries, and in idolatry or idleness, and in babblings, and in envyings and strife; wearing costly apparel; being lifted up in the pride of their own eyes; persecuting, lying, thieving, robbing, committing whoredoms, and murdering, and all manner of wickedness.” These unrighteous Nephites were not church-men; and as we have often seen, not only were non-church-men but also promoted social classes, hierarchies, and other violations of Nephite egalitarianism. It makes sense that they would be guilty of idolatry, since, like Noah, they accepted the values, lifestyle, and culture (including polytheism) of the larger outside world. Significantly, they also want to restore the monarchy. All of these factors suggest the influence of the outside world on the Nephites.
“Whoredoms” appears to be used interchangeably with “adultery” in prophetic calls to repentance. The behavior being denounced could be as simple as adultery and fornication, or it may include plural wives (Jacob 2; possibly Alma 10:11). Since all of the other significant sins listed are related to the incursion of Lamanite religion, probably at least an element of the Lamanite worldview is manifested in “whoredoms” or “adultery” as well.
What is most important in this catalog of sins is their effect on Nephite society, since Mormon says flatly these faults “brought upon them their wars and their destructions.” These sins, which were elements of the Lamanite lifestyle being promoted within the Nephite cultural area by Nephites themselves, were the sources of civil unrest. This unrest, as well as the unrighteousness that abrogated Yahweh’s promise of protection, was the reason for the Nephite “wars and destructions.” From Mormon’s moral perspective, the wars were caused by disobedience. From a social science perspective, they were caused by the internal divisions that resulted from accommodations to the Lamanite worldview (particularly its economic and political aspects), that altered the very definition of Nephite society. (See also commentary accompanying Alma 17:14 and Helaman 17.)