Perhaps it's an inherent human need and racism is just another version of tribal in-group thinking we're all saddled with. It could be "racial", or it could be geographic, ligual, socio-political, philosophical, religious, economic, etc. differences that balkanize our global identities.

Like Kris Kristofferson sang:

Everybody's got to have somebody to look down on
Someone they feel better than at any time they choose
Someone doing something dirty decent folks can frown on
If you can't find nobody else, then help yourself to me

That's why the Jerry Springer Show is so popular, isn't it?