As far as the Congressional Black Caucus' assertions of racism go. I think it's a total crock and I firmly believe they were attempting to bait the Tea Partiers. I know this because members of the House and staff usually take the underground tunnels to get back and forth. This group intentionally walked above ground in the midst of the protest in hopes that something would happen. It is malicious and cowardly. When they found nothing actually happened that they could use they chose to fabricate something, which serves to show how low in caliber they are.
I will end by saying that something happened during the 9/12 protest that I will never forget. As I was walking deep into the crowd on the lawn, I spotted a black woman sitting. She was somewhere between 55 and 65. When I met her eye she gave me a warm smile and mouthed the words "thank you". I smiled back and walked on.