and the best part of this thread for me is the link to the national brotherhood.
Many times you don't see what is not in large numbers. Is this thread asking for that one individula you might have seen once or people of color en masse on bikes? I find that people will mention a presence when a certian number of individuals are doing something as a group, that registers as numbers in an activity. However when there is just one individual going about that activity there is a call for questions of why there is a descrepancy of numbers for that activity
With that said IMHO many times its about networking. I ride with persons of all walks of life shades, etc...but there is a definite resonance when I join a group ride in the greater DC area and there are other members who are minorities. I assume its a harmony of interest but having people of like ilk around in any activity for the most part will make that activity more pleasurable. But not everything is enjoyable in a group sometimes the best rides are that solo 50-90 with clouds, cows, and cranksets