My perspective: Having been surrounded and almost run out of the lane I was in on the motorway by a notorious local bike gang (50+ of them), I know exactly what it feels like to suddenly be surrounded by a load of bikers. If something were to happen, then I imagine I would have crapped myself as well. It's certainly not an excuse, but perhaps it's a reason why the guy acted like he did. Fear.
Don't apply the UK road rules to the US either, lane discipline is different, and you can have people passing you on both sides of you at speed.
I've no idea what happened from the video, so unless there is new evidence...