It is Laban logic or Labanology. Killing the living to save the countless unborn through fear.
If you think about it, Nephi was a Hebrew murderer. He killed to save a record for people and that "record" Joseph Smith tried to sell the copyright to in Canada.
Joseph Smith got people to idolize a murderer.
There are always people willing to kill. It just takes some Labanology to get "greater good" killers killing.