Color blindness

I've had a series of interesting (to me anyway) experiences in the past few weeks. It started when, as a result of a class exercise, one of my students came up with a figure of Barack Obama hanging in effigy. It was not, I thought, a tasteful example of what we were dealing with, but beyond that I didn't think much of it. I did suggest that we needed, for fairness sake, all the other figures in the presidential contest to be hanging there too. We needed a McCain effigy, a Palin effigy, a Bush effigy, a Biden effigy, and so on.
It wasn't long before I got my chain yanked. Someone complained about images of lynchings of African-Americans, and as soon as I heard that, I know that I was in the soup (DEPARTMENT OF MIXED METAPHORS).
See, I didn't even think of Obama as an African American. I thought of him as a presidential candidate. Silly, naive me. And it is right that someone should have reminded me of the fact that he is African American and that the US has a woeful history of hanging such people out of hand and turning the whole thing into a picnic. If you don't believe me, google the words "Negro lynching" and see what you come up with. It's grim.
But, that's not my point today. It's that I was really, truly, colorblind. That's what Martin Luther King wanted, and I'm actually proud that I didn't see the African American part of it.
The problem is that people don't want me to be colorblind. Not really. They want me to always keep the memory of the lynchings in the back of my mind, so that "such things won't happen again." They seem to want to keep the sore open.
I'm not sure why this is. For one thing, there is no danger that we'll go back to lynching people. For another, it really gets in the way of the things that King and others were working for. It's a puzzler, and reminds me again how complicated people are, and how little you can trust what they say up front.