Looks like more information at the link:
“A witness from the scene says a man was walking through the anti-reform group to get to the pro-reform side when he got into an altercation with the 65-year-old, who opposes health care reform.
The 65-year-old was apparently aggressive and hit the other man, who then retaliated by biting off his attacker’s pinky, according to Karoli from DrumsnWhistles.”
Pictures show the anti-reform group consisted of 9 individuals.
Why did the pro-reform guy need to walk through the Anti-reform group to get to the other side of the road.