I didn't watch the clip but by the reactions here I can guess what it is about. Well, there is a simple answer why no one is helping. Can you be sure that the guy next to you will help too? Or will you face those thugs all alone? As long as you can't be sure that the others will stand by your side you should think twice before trying to help someone. What good is bravery if you end up dead or heavily injured because all the others continued to look the other way? Let alone that a lot of people are not in a fighting shape (me included). I could only serve as an extra sandbag in such a situation.
My question is more, what makes people so aggressive these days? There is no limit any more in the use of violence. People get beaten to death for minor things or nothing at all.

Sometimes my species is making me sick.