People perceive the world in their own vision and way.
Sometimes they see less, sometimes more.
Sometimes they see the distorted part of it, sometimes the truth.
Sometimes misperception occurs
Sometimes misinterpretation occurs.
And they spend their whole life defending it and forcefully instill their beliefs onto others at the expenses of physical strength.
Thus disagreement, argument, fight and war.
Like there are many ways baking a cake, there are many ways of life.
Different choices come with different outcome.
No single definite answer.
So long as we do not hurt each other, it is fine to bake different cakes.