He is where you are wrong if where truly "animals" and primal in nature then yes we would be just defended our own. Butttt the minute you bring in religion which teaches right from wrong then, there is a right from wrong
We are animals who invented religions, in the end these religions are battling each others for ...ressources. We are animals who like to think themselves being "something else", "something different", "something superior", but in the end our animal brain generates all these bullshits, period.
Life is intrinsically absurd, you only believe in what you ve been conditionned to believe to , you d be "convinced" of the oposite were you born somewhere else. Life is a constant struggle between differents forces and there s never a real definitive winner or loser as everything ends one day.