I think their teachings do. If they are convinced sealing guarantees their family is together forever, those spouses that have control issues may feel murdering their family is necessary (in a sick kind of way). The Vallow/Daybell case shows how the two totally believed the bom and said those scriptures told them to murder.
Susan Powell family same pattern. Matthew Shepard was another one. There seems to be a pattern in how the cult teachings condone murder of family. There was another a year or two ago in Salt lake where teenager killed family.
This is just my opinion and I could be off base. Any ideas?
Mark Hofmann was a con man, pure and simple. He used his LDS membership to gain access to the Mormon hierarchy to sell documents. I doubt he believed anything about the church. Susan Powell bought into the Mormon religion which blinded her from the behaviors of her crazy Mormon husband. Matthew Shepard was Episcopalian.
Ted Bundy converted to the LDS church during his rampage in Utah. Again a con man and murderer using the LDS church to his own advantage. I think all religions have some very bad people hidden in their ranks.
My understanding was that Matthew Shepard was killed by two rms who believed he needed to be killed because he was gay. I was told this by someone who was in their ward at the time. It could be incorrect but that is what I was told.