Wow. I just read that whole wikipedia article and had a fantastic time. Thank you very much for sharing

But to comment on your point: species DO pay for it in the long term when members murder or teratorialism.

Lions are not cannibals. Some lions are cannibals. A successful group of lions cannibals existing (and what a brutal and awesome-in-the-biblical-sense story it is!) does not mean that it pays for the lion species as a whole to have groups of cannibals existing.

In fact, I could only see the “proliferation of groups like this committing atrocities” reach a tipping point for a species - not murdering when this murdering happens will make you cease to exist. So if the species doesn’t have a reason to reach the extreme where this NEVER happens, then it will quickly reach the point where this ALWAYS happens