Hard to tell what started the (metric) road rage much less the "group think", probably (something like) a close call on a lane change, after that, the taunting began and the camera went on. The injury resulted when the rider slowed way down and faked a stop. The Rover bumped him, he went down and the driveover busted his legs. Match+fuse+testosterone=BOOM.
My group is older, we wouldn't have reacted that way, but I have to admit, thirty years ago.............we might have done something equally as stupid, if not worse. The driver probably deserved a major ass chewing and a "corrective interview" about watching for motorcycles. The whuppin' they gave him is going to result in some time in County. There is a lesson here, but I have to agree, under the circumstances, "restraint" might be hard for any of us to find at that moment.
Unfortunately, several of us that carry might have shot "helmet guy". No winners here, and as the post suggests, a "Black Eye" for all of us. This is very insightful stuff, raises many issues, good job guys.
OWL