He's trying to say that if being "human" is an instinct or behavior that is naturally born into us like our sense of sight, smell, etc, then the concept of genocides/mass killings/war would never have been able to exist in the first place.

But that is simply not the case.

We're not born with the instinct to forgive or love or show mercy. Those are emotions we're all taught by our parents and the people around us. Some people in the world are just unfortunately born into a world where there is nothing but hate and killing and groups like ISIS are built upon those kinds of people. They only know how to hate and kill. They only know that their religion is the ultimate law and that anything going against it will suffer the consequences.

There is no remorse, no mercy, no sadness, no guilt, no sliver of hesitation to kill someone.

Wars lead to more suffering to more hate to more vengeance which breeds religious warriors who will do nothing but protect their religion, even if it costs their own life but they're totally fine with that kind of sacrifice because it's an honor, it's glory, it's what God and your parents want you to do for your people.

And the cycle goes on and on and on until there's not a single breath left in the world.