I think people get it from their parents or have heard it somewhere else. Some people think it's funny to bring pain on other people or they do it just to make themselves feel better. Some people do it to fit in. I blame social studies class.
I think it starts with an influence that gives one the mindset that one race is superior to the other. But that's only how it starts. It's then kept through ignorance. And arrogance is a choice that can be changed.
Because they believe that people with different colored skin are going to be different. And they pick on them because they think they're in a higher class than them. People were killed because of this. I hate it. Were all equal. Regardless of the class, or church, or race.