What BY is teaching, I believe, is not Blood Atonement. Blood Atonement is about shedding blood of an another animal or human to pay for your own sin, ie Crusades, Jihad, etc.
What BY was teaching, in my opionion, was the doctrine of Sherem and the malafactor and what one must do to have a hope of forgiveness in Christ after committing a seemingly unpardonable sin.
This could be a very important doctrine that Satan hates because there's many people who, no doubt, feel stuck in deep dark conspiracies and they stay in them believing falsely that they've committed so much Sin, that they are beyond the reach of the atonement of Christ and they've committed the unpardonable sin and then there's no hope for forgiveness for redemption .
But, remember the Lamanites who preached the gospel of Christ to the more wicked part of the Gadiantons and by doing so, destroyed the Gadiantons and secret combinations from among them . and I think it was teaching how people could be forgiven of a seemingly unpardonable sin that made this possible.
what Sherem and the malefactor did was go through the steps of repentance.
1. accept and defend Christ
2. accept that they sinned
3. publicly confessed sin
4. freely accepted their punishment without appeal or plea deal. (even capital punishment)
I dont think having blood literally shed on the ground is a necessary ingredient. Again, If we believe in Christ, only His blood forgives sin. But the steps to repentance do require restitution and paying our social/societal penalties. (Why Sherem knew he was going to have to die).
What we get out of this is trustworthy confessions about what is really going on. Multiple witnesses sealing their testimony of their many sins and the sins of the great conspiracy with their own blood (so-to-speak).
The comspiracy loves to send us false insiders/defectors who claim to be "born again", but they never comfess or are punished for their sins. If they were true insiders they woukd have many terrible terrible sins to confess wgich is how the conspiracy prevents itself from being infiltrated.