It is reported that some use this teaching to justify the murder of those who turn from mormonism, or got in the way of their lust for women and power?
Thomas Coleman murder
An example used by some to illustrate the alleged practice blood atonement is the 1866 murder of the former-slave, Thomas Coleman (or Colburn), who was in good standing as a member of the LDS Church. As Mormon historian D. Michael Quinn has documented, Coleman was apparently secretly courting a white Mormon woman. At one of their clandestine meetings behind the old Arsenal (on what is now Capitol Hill in Salt Lake) on December 11, Coleman was discovered by "friends" of the woman. The group of vigilantes hit Coleman with a large rock. Using his own bowie knife, his attackers slit his throat so deeply from ear to ear that he was nearly decapitated, as well as slicing open his right breast, in what some believe was a mimicry of penalties illustrated in the temple ritual. Not all of Coleman's wounds correlated with the temple ritual, however, since he was also castrated. A pre-penciled placard was then pinned to his corpse stating, "NOTICE TO ALL N*****S - TAKE WARNING - LEAVE WHITE WOMEN ALONE." Even though it was the middle of winter, a grave was dug and Coleman's body was buried. The body was disposed of in less than three hours after its discovery. Less than twelve hours after that, Judge Elias Smith, first cousin of Joseph Smith, appointed George Stringham (a Mormon ruffian and vigilante with ties to Porter Rockwell, Jason Luce, and William Hickman) as the foreman of the Coroner's Jury; they briefly met and summarily dismissed the case as a crime that was committed either by a person or by persons unknown to the jury, abruptly ending all official inquiry into the bizarre murder.[
The difficulty here is that "blood atonement" was supposedly applied to endowed Mormons who apostatized. While Coleman may have been a Mormon, he definitely wasn't an endowed member, nor was he an apostate. Assuming the reported circumstances of his death are true, they are a tragic example of racism and lynching, one all too common in that time period.