Am I a racist? I don't know -- I honestly don't know.
Do I notice that there are differences between humans that are physical (rather than just in their personalities)? Of course I do. Does it matter to me? That's where I don't know.
Once I get to know a person, then I can honestly say that physical differences don't matter -- or at least their import wanes until they eventually disappear. But that could be true of skin colour, physiognomy, or even genetic anomalies like Down's Syndrome (my best friend's brother-in-law has Down's). Where I notice them at first, with deeper connection with the person within, they take on less and less significance until (I hope) one day they have no place at all.
My own suspicion is that it is part of our human nature to notice what connects us and what separates us from others of our kind. This no doubt is the result of natural selection for the protection of the tribe. But we have been successful as a species world-wide (rather than as a whole lot of different, tribal species) because we have been able to make that connection to that humanity within that connects us all.
But I still know that I notice differences...I am as I am made to be. I don't know if that makes me a racist. I hope it doesn't.