One definition of subtle is something that is "so slight as to be difficult to detect or describe (American Heritage)." So, with that in mind consider the details of the following very short story:
I was in the city the other day and I got on the elevator. There was a really tall African American standing there. He kindly asked me what floor, so I told him, and he pushed the button for me. Well, I got off on my floor and wouldn't you guess, I had left my glasses in the car in the parking garage. Well you know I can't see anything without my glasses, so I had to go all the way back down to the parking garage, get my glasses, go back up to the 8th floor. What a day!
So, this is not a riveting story by any stretch of the imagination. But it does contain something that I seem to be sensitive to. For lack of a better term, let's just call it subtle racism.
In the story, there is absolutely no reason to mention that the man on the elevator was African American. It has no bearing on the story.
So, you might say, "The reference was completely innocent." Possibly, but how many times have you heard someone make reference to the white guy on the elevator? Perhaps this same article could apply to African Americans who would do just that. I couldn't say.
But I know that, when you sharpen your eyes and ears you will discover nestled deep within the details of many stories and actions is this little chestnut called subtle racism.