Okay... one more for you.
Lets say it wasn't just a few things... but everything you have. Lets also say your insurance didn't cover a *large* portion of it. Say, for instance, you ran a home based business and that sort of thing isn't covered by home-owners. Lets say you got cleaned out. But... you owe people money for the inventory, lets just say it's alot -- over $100k, interest bearing. Basically, the robbery would screw you up for the rest of your life. It's not just stuff... that would be your life, ruined. Stuff can be "more than just stuff."
Now... it's the principle. These guys weren't pulling a huge heist that day... but they get away with it today, who says they won't move up to big jobs? They probably will, if they got away.
I'm not arguing to banish the system. But, if someone witnesses some stuff going down you can't expect them to just SIT there -- especially if it is right next to them and someone they know well being affected.
Maybe you disagree *shrugs* thats fine. If my neighbor was being robbed and I could do something about it, I would. But maybe I give a crap about my neighbors and you don't? Maybe killing them wasn't the best idea... of course, with a shot-gun aiming at certain areas is a bit hard.