I kinda thought that the SUV driver might have done something to cause this to happen. I highly doubt the bikers went out looking to target some random person. That said, that doesn't excuse the threatening behavior.
Did you watch any of the other videos I linked to of the groups behavior and how they were driving? They were weaving in and out of traffic, driving in the wrong lanes with on coming traffic, passing on shoulders, riding on sidewalks, running red lights, etc.
They were a bunch of jackasses.