Consider the fact that this was a long standing social equilibrium:
During an undetermined time period preceding European contact, a gargantuan, humanoid spirit-God conquered parts of the Sepik region of Papua New Guinea. … Nggwal was the tutelary spirit for a number of Sepik horticulturalist societies, where males of various patriclans were united in elaborate cult systems including initiation grades and ritual secrecy, devoted to following the whims of this commanding entity. …
a way of maintaining the authority of the older men over the women and children; it is a system directed against the women and children, … In some tribes, a woman who accidentally sees the [costumed spirit or the sacred paraphernalia] is killed. … it is often the responsibility of the women to provide for his subsistence … During the [secret] cult’s feasts, it is the senior members who claim the mantle of Nggwal while consuming the pork for themselves. …
During the proper ritual seasons, Ilahita Arapesh men would wear [ritual masks/costumes], and personify various spirits. … move about begging small gifts of food, salt, tobacco or betelnut. They cannot speak, but indicate their wishes with various conventional gestures, …
Despite the playful, Halloween-like aspects of this practice … 10% of the male masks portrayed [violent spirits] , and they were associated with the commission of ritually sanctioned murder. These murders committed by the violent spirits were always attributed to Nggwal.
The costumes of the violent spirits would gain specific insignia after committing each killing, … “Word goes out that Nggwal has “swallowed” another victim; the killer remains technically anonymous, even though most Nggwal members know, or have a strong inkling of, his identity.” … are universally feared, and nothing can vacate a hamlet so quickly as one of these spooks materializing out of the gloom of the surrounding jungle. … Nggwal benefits some people at the expense of others. Individuals of the highest initiation level within the Tambaran cult have increased status for themselves and their respective clans, and they have exclusive access to the pork of the secret feasts that is ostensibly consumed by Nggwal. The women and children are dominated severely by Nggwal and the other Tambaran cult spirits, and the young male initiates must endure severe dysphoric rituals to rise within the cult. (more)
So in these societies, top members of secret societies could, by wearing certain masks, literally get away with murder. These societies weren’t lawless; had these men committed murder without the masks, they would have been prosecuted and punished.
Apparently many societies have had such divisions between an official legal system that was supposed to fairly punish anyone for hurting others, along side less visible but quite real systems whereby some elites could far more easily get away with murder. Has this actually been the usual case in history?
Here's an anthropologist's take on why men's cults were so prevalent: https://traditionsofconflic...
He makes no mention of ritual murder as described in the post (except, perhaps, as punishment for women who viewed the sacred instruments). This makes me think that masked murder is a non-central example of these secret societies' activities.
Oops:"literally" -> "to refer only to death causation rather than as a euphemism" in my comment above.