Why is everyone so surprised that this happens on a regular basis. We live in a society on which violence is an accepted form of interaction. Someone insults you, beat them up, someone flicks you off on the freeway, run them off the road. We go to the movies and we think nothing of seeing someone dismembered, blown up, shot, tortured or what have you. If someone is getting a good old fashioned porking, that is off limits because it is "bad". Never heard of someone getting porked to death.
I have not been able to find any stats that show if the per capita murder ates have gone up or down over the past 100 years or so. I would not be surprised if they have gone up substantially.