covert leaders of ancient civilizations knew what they were doing

the reason that ancient civilizations insisted on doing human sacrifices 

were that when unrighteous humans reproduce with unrighteous humans 

then their children devolve genetically 

and their behaviours devolve to become something else than human behaviour or animal behaviour 

their behaviour become disgusting 

the covert leaders of ancient civilizations knew what was happening and set in motion processes that would exterminate unrighteous humans 

official leaders explained to the public that some people were to be sacrificed to the god or gods 

and then unrighteous humans were sacrificed