Even Mormon’s personal history, as contained in Mormon 1-7, is an abbreviated work. He likely spent a lot of time cataloguing every wicked abomination of his doomed nation in his full account. This project would have started at the age of 24 when he first obtained the Large Plates of Nephi. According to tradition, he would have recorded all the secular and ecclesiastical history of his people. (Even though we have his abbreviated history, how interesting it would be to read that record!) He must have felt like Ether before him, as he dwelt in the cavity of a rock he made the remainder of this record, viewing the destructions which came upon the people (Ether 13:14).
So when we read Mormon 1-7, we must understand that Mormon is not painting the picture as graphically and vividly as he could. He is sparing us the gory details in an abridgement of his own record, behold, I Mormon, do not desire to harrow up the souls of men in casting before them such an awful scene of blood and carnage…therefore I write a small abridgment (Mormon 5:8-9). Still, he paints a pretty graphic picture, there was blood and carnage spread throughout all the face of the land…it was one complete revolution…I saw thousands…heaped up as dung upon the face of the land…And it is impossible for tongue to describe, or for man to write a perfect description of the horrible scene of the blood and carnage which was among the people…[they] did take many prisoners both women and children, and did offer them up as sacrifices unto their idol gods (Mormon 2:8,15; 4:11,14).
In an epistle to his son, Mormon felt free to describe their wickedness even more graphically, they thirst after blood and revenge continually…they feed the women upon the flesh of their husbands, and the children upon the flesh of their fathers…many of the daughters of the Lamanites have they taken prisoners; and after depriving them of that which was most dear and precious above all things, which is chastity and virtue…they did murder them in a most cruel manner, torturing their bodies even unto death; and after they have done this, they devour their flesh like unto wild beasts, because of the hardness of their hearts; and they do it for a token of bravery. (Moroni 9:5-10) If this depraved wickedness isn’t enough, there is another record written by Mormon which describes much, much more. This Mormon referred to as his full account.