Here's the thing. Was the truck driver wrong? Yes! At the point where he illegally passed by crossing the double yellow is where they should have known something would go down. Then when he swerves into the rider is the point where I stop pursuing and turn the video into the cops. From what I saw at the beginning of the one video, the riders were not doing anything illegal. There was a large group of them but they were still in motion, not stalling traffic from what I could see. Also down a residential street where the truck drivers actions were even more dangerous to surrounding pedestrians. Truck driver at fault no doubt!
Where I think the riders failed is letting their pride, emotions and/or egos get in the way of reasonable decision making. Additionally, the "mob" mentality that their strength in numbers increases their ability to do something about this guy.
Just my quick .02 on the whole thing.