Humans have clearly moved on from a purely animal psyche, contrary to what some have suggested. Although some of our tendencies can be traced back to the pack mentality of our evolutionary predecessors to say that we are somehow still governed by those instincts is inaccurate. Influenced at times, yes. Compelled at others, sure, but not wholly governed.
Our society would be completely unsustainable if we still succumbed to our instincts’ every whim…. Take the concept of monogamy: as far as I’m aware it is unheard of in mammalian species; certainly amongst our closest relatives. Were I still animal, I should be running around, fathering wherever possible and not hanging around to find out what my offspring all look like… Although this does happen, we tend to frown on it, rather than condone it. Not very mammalian at all…
As for CEOs and politicians, I expect that to be traced back to the mammalian need to acquire alpha male status. This has to do with the “s” word, not killing.
On the point of killing: Animals, as most will have noticed, do not have guns, hellfire missiles, or A-bombs.
When they kill, it is up close and personal. It is a risk as the other party, be they prey or rival, will have their own weapons to deploy. Therefore animals will not kill unless fulfilling a need, and that need outweighs the risks.
This need can be and usually is, in the case of predators, for food. This can also include killing to protect one’s territory. Killing can also be part of a bonding activity in some social animal groups as well as a means of honing life skills needed in adulthood.
Sometimes it arises because something happens that stimulates that behavioural pathway, such a thrashing swimmer will trigger the hunt reflex in a Great White. It is not that the Great White suddenly fancies killing a human. The human gave the wrong signals at the wrong time.
By contrast, killing is not, as some seem to suggest, some kind of funtime hobby.
It seems to me that killing for pure recreation is something that has evolved from Mankind, not been retained from primitive ancestors.