Karma is just a placebo (so to say) of revenge. When something happens that seems like it was revenge for a past action, it is labeled as an effect of karma. Otherwise, it's just bad luck. Karma and luck are the West's 'Magic'; the same goes for good things too. Although, the theory is nice in terms of reassurance and self-critique.
With that said, I do hope that they get what they deserve. The video was sickening and I ended up stopping it after only watching a few seconds of it. The video will undoubtedly be good for the courts because you can't deny it or downplay it. It also spreads the news far faster, which is good because more people will become outraged by the events shown in it and perhaps give things like this more thought. The video is also bad because unfortunately some people will undoubtedly find it funny and simply mock it. Most things in life are double edged swords with a good and bad side, this video is one of them.
The event shown in the video is without a question, horrible.
As others have pointed out, this isn't the only case of someone being beaten. In general, our current society is terrible. This happening before to others, is irrelevant to it happening in this case (with the exception of the previous ones not preventing this one). It only strengthens the claim that society is (and pretty much always has) been an ugly thing.
Sure makes you question the intentions of mankind more and more.