Please read "armenarmen" comment, above: "those humans not that are not members of their tribe are not people". Albeit difficult to grok, it seems pretty clear to me.

armenarmen said that happens in tribal life; but not that it was unique/specific to tribal life.

That's not my understanding, as he answered "This." to a post containing "Tribal politics are brutal, and any ancient community would have a very strong sense of identity, and about who belonged and who didn't. Life was way harder...".