I am at a loss to explain why it is this happens so much these days. I have seen accidents where people will just drive through the carnage and completely ignore it. I even know of a biker who was led in the road in obvious agony and i guy pulled up next to him, rolled down the window and shouted at him to "get that pile of **** out of my way"!
Sadly people have very little compassion anymore. Sad sign of the times.