I think the thing that was run over looks like a doll/robot. I don't believe it's even remotely real. Look at the reactions of people, people would not have no reaction to an actual human body. Think about it, even if people were going to do nothing, they'd avoid the body in case it was diseased. This is not just lack of compassion, this is lack of self preservation. Also, look at the reaction of the person who finds/picks up the the body at the end of the camera footage. Is she pleased, showing off, what she found? If you look carefully, you won't see any blood either. The liquid on the ground appears to be completely clear rather than red (though the poor footage quality makes this a very hard task). Ultimately I think the Chinese people are just as compassionate as we are in the west, and I cannot believe this video on the evidence presented.
All of these inconsistencies, combined with the obvious intent of the video to create an emotional reaction, suggests to be that something here is not quite genuine. I would like to know what the Chinese characters actually say - I suspect they would give us more insight into the truth behind the video.
As for the dog, it was beautiful, yes, but I bet you can find videos of dogs eating other dogs in that situation too. It depends on the relationship of the dogs and the individual dog themselves. As I said, beautiful, but not representative of the species as a whole.