Actually, I saw more black men and women at the convention than I expected to see. I was pleasantly surprised. And I was watching C-Span.
I noticed the same thing too. I was sometimes flipping over to MSNBC just to see if anyone had had blown a gasket yet, and got a chuckle when they were showing crowd scenes, focusing on a person for like 5 seconds or so before moving to the next person. They put up a black lady, but she didn't stay up but for a second at best. You just know some camera guy was hearing in your earpiece "what the f*** are you doing putting anyone but old white men in suits on camera????"
CSPAN did a good job of showing a cross section of actual attendees IMO.