Humans WILL always fight with each other, period

I just want to highlight an interesting human behavior, Fighting.
Since humans evolved from chimpanzee/ape, fighting between humans remained same but name or cause of fighting's  keep changing ...

Humans fighting within family (brothers or sisters, sometimes they kill each other for property etc)
Humans fighting with neighbor area or district or states
Humans fighting with different languages (Europe , english vs french) or caste (eastern Asia)
Humans fighting with different races
Humans fighting with different different ideology (communism, capitalism)

Humans fighting between religious fundamentalist

Nothing can unite humans, lets analyze few hypothetical scenarios: 

a) If all humans on the earth become white or black, then they will fight country wise each other for resources or fight for language superiority or custom superiority. for ex: In Africa, people fight/kill between different tribes. 

b) If all humans on the earth converts to Christianity, then they will fight based on the races or color or the way of praying Christ.

So fighting/hate/misunderstanding is constant, just name changes.