Racism is nothing new, it's been going on since there were humans.

I believe the fearing what is different was/is built into the human mind for survival during it's infancy.

To survive as a caveperson, especially a pre-fire caveperson anything that wasn't you/your tribe/whatever was competition for resources.

It's something that is now in the human mind that isn't really needed anymore. Like your appendix.

Problem is in the history of Earth humankind has only been around a very short time.

It's something that we will probably evolve out of as time goes on.

Until then you have to use you intellect and reason to rise above those ancient human instincts.

Or, I could be completely full of shit.