Where does your (Christian) Bible allow human sacrifice?
Right there is your problem as you see Jesus Christ as merely human. It’s not imputed righteousness for nothing bud. Even Abraham the father of all those marked for heaven had his righteousness imputed to him after an act that at first appears to be an almost human sacrifice of his son, yet later we find out it was a foreshadowing to show God’s great love for us that he spared not even his only son.