True he wasn't technically at gun point.
However, how was the rider a threat to anyone by that point? He couldn't run the officer down like you could with a car (he would just end up on the ground). He was boxed in.
I would also challenge the notion that the rider is an 'idiot' and a danger to himself or others. Of the 3m39s long video, there's only about 10 seconds (starting at about 0:35) where he accelerates significantly faster than the surrounding cars, and that was clearly to get around a group of cars/transport trucks. Otherwise, he was going just slightly faster than the general flow of traffic. Both of these tactics are basically inline with conventional motorcycle safety recommendations: http://www.sportrider.com/ride/146_9508_motorcycle_riding_ti...
Also, it appears that the officer is hiding his gun when the marked cop car pulls up behind them. I think it's worth pointing out that they charged the rider with wire tapping (which the judge ultimately threw out) and raided his house after discovering the video had been posted on YouTube. It's hard not to interpret these actions as embarrassment on the part of the police. Why would they object to the video being posted if he was completely justified?
The video wouldn't be approaching a million views on YouTube if most people agreed that his actions were as reasonable and mundane as you imply. He didn't show his badge or even identify himself as a police officer until after charging at the guy with gun in hand. That doesn't strike me as 'professional'.