My takeaway from all this?

TSA tells me I have a responsibility to keep an eye on my belongings at all times. When TSOs prevent me from doing so at the checkpoint, they tell me that there are cameras and other TSOs to ensure the security of my bags.

This guy could just as easily have walked off with my locked bag and no camera or TSO would have stopped him. I will be even more insistent in the future in trying to keep personal control of my belongings at all times.