You don't have to travel to the US to find that, enough of that in Western EU where many of us come from.
Racism is a basic human survival instinct, from the times we used to live in tribes.
Can't get rid of that so easily, as it is in our survival genes.
Especially not with all the positive discrimination in the western (white) world.
You get so sick of it, that they actually create racists with it (or maybe that is just the purpose of all this propaganda, keep it nicely divided).
Besides the fact that you can miss out new experiences (good or bad, but at least interesting) by holding on to racist thoughts, I think people should have the right to have these thoughts. It is up to the individual to choose to let those go or not.
And the least thing that is wanted is surpressed anti-racism politics, like we are living in now.
And if everybody would be really honest, we all hold initial judgements based on al the first things we see in somebody, one of which the breed is one