The final section of what is now called the Words of Mormon picks up during the early years of King Benjamin’s reign, when he had to deal with "much contention" and "many dissensions" among his people. Verse 15 states that "there had been false Christs." The word "Christ" is equivalent to the word "Messiah" in Hebrew, which means "anointed one." In other words, "there had been many false [Messiahs]" in the land. It is of interest to note that the two names "Mosiah" and "Messiah" would have been very similar in Hebrew. "Mosiah" is also the way in which the word for "Redeemer" is vocalized in Hebrew. It may have been that King Benjamin had to deal with people claiming that it was their job not just to be a religious leader (a priest or anointed one), but to be a political leader of some kind.
The record goes on to state that "there had been false prophets, and false preachers and teachers" and they were all "punished according to their crimes." Was it a "crime" to preach falsehoods among the people and to hold oneself out as a "Messiah" to the people? The people of Zarahemla had chosen to live under Nephite law, which was the Law of Moses. Under the Law of Moses, a person could be severely punished for causing dissention by spreading falsehoods and holding oneself out as a prophet when one didn’t have that calling from God. Freedom of religion did not exist in this world—especially when religion was being used for political purposes. During the early part of his rule, King Benjamin had to deal with the formation of sub-groups of people with different religious beliefs and political motives. Benjamin was able to unify his people by creating a unified pluralist society where two groups of people of different political and historical backgrounds were accommodated and could thrive through the making and keeping of a centralizing covenant with God, their Heavenly King. The inspiring peace that King Benjamin was able to accomplish under this unique situation stands as a model for governing in a religiously pluralistic society.
Like King Benjamin, Mormon himself had wrestled with the problem of false prophets, false preachers, and false teachers among his people. He was familiar with dissensions and the stiffneckedness of people. However, Mormon had a much larger population to deal with and probably did not have the benefit that King Benjamin had with "many holy men" and "holy prophets who were among his people" to establish peace in the land. Mormon and his son, Moroni, were among the few lone outliers of remaining righteous leaders among their people.
Book of Mormon Central, "How Did King Benjamin’s Speech Lead to Nephite Democracy? (Mosiah 29:32)," KnoWhy 301 (April 17, 2017).
Book of Mormon Central, "How Was Mosiah a Type of Christ? (Mosiah 26:12)," KnoWhy 104 (May 20, 2016).