Around 2,000 years ago, human creatures evolved into intelligent beings. That is when our ancestors began to categorize everything into groups and again classified and generalized those groups into smaller groups to increase their chances of survival. Let’s say in a particular tribe the men paint yellow stripes on their skin. One day while hunting and gathering, he meets another man from another tribe who has blue lines painted on him. They exchanged spear designs and ideas, and study each other’s weapons and then walk away feeling satisfied. Continuing on his way, this same man meets another tribe member who has red stripes on his body — this time when he goes to greet him, the man hits him on the head and steals his spear.
Our hunter now associates blue stripes with good and red stripes with being very bad. He, therefore, generalizes that red striped people can’t be trusted and does so to ensure his survival. The reasoning goes this way; why take a risk and trust a tribesman with red stripes again? Once he gets back home, he tells his tribe about his venture, and now everyone distrust red striped people, and are open and willing to meet the blue striped men. Now all this is based on the actions of one single man.
If we forward to modern times, we realize that people are still making those same snap decisions about whether to trust a race or a group based on the actions of one or two individuals. Sadly we promptly categorize people based on apparent physical features such as dark skin, white complexion, and Asian eyes. It would be better if we could analyze their socio-economic backgrounds, but that isn’t as immediately obvious by looking at their faces.
We also tend to categorize people into two very basic categories the good people and the bad people, even though everybody has good and bad traits. Also, we always tend to see our own group as being the good group, the righteous one, and groups that don’t like us are automatically bad groups.
Essentially, as it as always been through time, you’re either with us or against us.