I have seen a lot of these bikers on YouTube too- speeding on highways, doing wheelies with cars around etc.
I can tell that the bikers(not all of them) were looking for a victim to harass.
As you can see in the video, the biker deliberately braked and wished that the sub hit it- an excuse to show anger and cause a fight. You can also notice that the SUV owner was pissed off as the bikers weren't giving him way and kept on blocking him.
The biker also knew that if a fight did happen- it would have been the SUV owners versus most of the bikers. If it was a biker alone, he wouldn't have the cohones to pick on him lol.
Sometimes I wished I could do that in pakistan too!
Some bikers are just annoying as **** and I hope that I had a SUV with massive steel bumpers. At least I won't have to brake and dodge bikers on U-turns who keep shoving their front wheels on the road.