I've watched the video, and yes the local chaps reaction was poor, but if somebody had hit my car and then tried to drive away, I don't think my reaction would be very different?
Everybody try's to remain considerate and calm, but sometimes the wrong buttons get pushed.
As for the arrest of the guy filming, same in the UK and many other places, you cannot take pictures of people, bridges, police stations etc, so it's not just the UAE.