What's changed is the ability to travel anywhere in the world and to project technology. It used to be a much slower process and oceans kept things split and at a much slower pace.

It’s literally in our DNA to cooperate with each other.

Is this supposed to be a scientific challenge to me? Like can you point to it? What I see is that forming gangs and armies is a human behavior characteristic. Did you here how Japanese people behaved in attacking all over the world, even Perl Harbor, in the 1920's to 1950? Did you know about the Crusades of people from Europe going all the way to the Middle East to attack each other over a book that says one part of land is more important than others? Are you aware of the complete destruction of cultures by the Spaniards when they came to the Americas?

Your answer seems wildly simplistic.

It’s literally in our DNA to cooperate with each other.

Mutually Assured Destruction, MAD, seems to be in the human behavior once technology comes into the picture. Multiple human groups arrive at the same solution. China, USA, Russia - and form alliances around it. People barely protest it and vote for politicians in democratic (much like voting on Beehaw) methods to continue to support it. It is reality of how humans address their differences, with 45 minute delivery of nuclear destruction ready 24 hours a day, 365 days a year.