Why are we racist?

I was reading about the Canadian trial of Gerald Stanley for killing Colten Boushie. I know very little about the circumstances. It seems there's a lot of anger, a lot of strong emotions, and so there should be.
I understand why Stanley had a gun, and why he shouldn't have had a gun. It's bizarre that it's so easy to get a driver's license, and even easier to own a gun. Not only should there be a series of careful psychological exams prior to having a lethal weapon, but also annual exams, all without being subsidized, at the very least. Obvious to me, apparently not so clear for too many people who are sadly afraid and confused.

It's important to know when we're thinking from fear, and when we're thinking from love. It's not as easy as writing opinions. It's not as easy as having a soapbox to stand on, although we all need to be heard, we all need to express our concerns. We have elders for a reason. (I'm not an elder).
As a nation, why do we treat racism as something we can deal with later?
Apparently peace, love and understanding are harder for some than for others.
There is a better way to live, of course. There are people living with dignity. There are those who think before they speak. Not an easy road, but a good one.