Hmmm well, getting back to one of the earlier posts, blood is symbolic of life. I remember reading a story of a doctor who had to give his own blood to save a patient because the patients family members would not because it was his lifeblood.
I think there is a lot to be learned from the symbols used in religion, like blood. It's not about murder but about life and laws, like the law that God set in place...or was in place because of who God was... That, blood is neccessary for the forigivess of sins. And it is a widespread symbol of life across all cultures, maybe a useful symbol to use.