I can’t tell if this is stating the obvious or not:
The ancients could kill you in a million different ways and give you a million different reasons why it needed to be done. In much of the pre-modern world, ritual sacrifice was framed as necessary for the good of the society at large — the only way to guarantee, say, a plentiful harvest or success in war.
But the priests and rulers who sanctioned such killings may have had another motive, a new study suggests. An analysis of more than seven dozen Austronesian cultures revealed that the practice of human sacrifices tended to make societies increasingly less egalitarian and eventually gave rise to strict, inherited class systems. In other words, ritual killings helped keep the powerful in power and everyone else in check.
That finding might seem intuitive — societies in which some members are habitually killed probably value certain lives over others — but it has broader implications, the researchers said in the journal Nature. It suggests a “darker link between religion and the evolution of modern hierarchical societies,” they write, in which “ritual killings helped humans transition from the small egalitarian groups of our ancestors and the large, stratified societies we live in today.”