Nephi does not pull any punches. The names he calls them (v. 21) are certainly fitting of their present character, but it is not a way to win friends. Perhaps he was angry because of their thinking they could buy him off (v. 20 above). His next purpose, however, was to show them he knew of their wickedness. Since he had been absent while preaching in the north, they may have thought he hadn’t been back long enough to find out the extent of their wickedness and abominations (v. 23).