Note carefully the response that Anti-Nephi-Lehi, the King, gives to Ammon. He is concerned that they will not be accepted among the people of Zarahemla because of the “many murders and sins we have committed against them.” The “sins against them” we may surmise have something to do with the battles, but what of the murders? These are the same murders that made their repentance so difficult, and the greatest likelihood is that they are to be seen as part of the religiously sanctioned and encouraged human sacrifices that would have been performed among the Lamanites.
Even though the actual number of men in the people of Anti-Nephi-Lehi who might have participated in raids or battles with the people Zarahemla would have been significantly smaller than the entire population of the group, nevertheless the King presumes that the entire people would fall under the same condemnation. As participants in the culture of human sacrifice to which some of the Nephites must have fallen, this fear would make some sense. The King would rightly be concerned that the Nephites would accept a people who had used captured Nephites as human sacrifices to pagan gods.