There will and always have been groups of people who will find reasons to dislike other groups of people. Even if we all the same skin color there would be discrimination based upon heritage, eye color, religion, or some other factor. It seems as though it's human nature for some people to (need) to feel or believe they are born "superior"
If it's not racism then it's a social economic status one uses to separate themselves from the lower class or mass population. (VIP sitting areas in nightclubs, first class travel on planes, 5 Star hotels and restaurants, Penthouse Apartments, beach homes, yachts, mansions, fame, money, and power.) Truth be told most people don't want pure equality where everyone is treated the same. What they want is an equal opportunity to become "special".
In their eyes you're either "special" or a "nobody". Equality equal mediocrity. They need to be able to measure and compare themselves to others. Instead of making all schools grade on a simple "pass/fail: basis people want to know if their GPA or score was highest or higher than most others.
Everything is ranked as the "best", "good", "average", and "poor" from schools to cars. We're always trying to find a way to "stand out" from the rest of the world by pointing to something that says "I'm the best or the top" (whatever) because.....etc
Simply put most human beings have a (need) to find ways to stroke their egos.