I may be convinced that the ultimate evidence of evil in any given society—religious, geopolitical, tribal, or otherwise—is the presence of human sacrifice, whether by willing ritual or coerced murder.
This has manifested in many ways over millennia. Demanding human sacrifice to appease the gods. Killing anyone but yourself to survive.
At its most blatant it involves genocide. At its most vile it involves capturing and or breeding humans for the purpose of propitiatory sacrificial fodder. Farming slaves to offer as sacrifice. At its most deceptively nuanced, it involves complex manipulation of society to drain the lives of the masses to feed into the lives of the powerful few. This has existed in some form in every major organized system of human society.
Consider even Judaism, which at its core involves sacrificially slaughtering animals in droves as a substitute for their owners. Why were animal sacrifices necessary to appease Yahweh? If they are not necessary now, then they were never necessary. That is, they were never necessary for Yah to be appeased, but for the people to trust that Yah was in fact a god and provide evidence of his presence among them.
The whole point of Eden is that nothing has the need to kill anything else, but to cultivate life eternally.