Here is a CNN report showing reporter Dana Bash and CNN's Don Lemon talking about reports that some African-American members of Congress were "taunted" and "followed" by protesters on Capitol Hill yesterday, and that Rep. John Lewis says "a racial epithet was hurled at him by some protesters." Rep. Emanuel Cleaver also reported that he was "spat upon" by a protester.
The "taunted" and "followed" with protesters shouting "Kill the Bill" is perfectly within bounds. But the shouting of racial epithets is clearly not. The fact that out of thousands of protesters present you have an isolated report like this certainly does not mean it represents the entire group of protesters.
The CNN video above has no video of the incidents, just talking heads talking about it. The video below shows some of the members of Congress in question walking through the crowd. You can hear the "Kill the Bill" shouts, but in this clip you see or hear nothing beyond that, other than booing. That certainly does not mean the isolated incidents did not happen. This clip is only from one vantage point along their route. The actions of those few against Lewis, Cleaver, and Frank should be condemned by all. But it does show it was not indicative of the entire crowd of protesters: