I would say that it's a way to process something horrific.

I, personally, could not process 9/11. I was driving on a highway (a couple weeks later) in an area where you could see where the towers had been. There were dozens of cars pulled over and the people were simply staring. They could not process it either....

Sometimes, when something is awful, we literally can't believe it. And I think watching repeatedly, helps you to find a place in your brain to "put" the information that your eyes are sending so that it can be processed in some way....

Just an opinion....