I wonder how many people commenting actually hunt. I've seen several moose out while hunting elk and, although it's not excusable, I can see how someone would make this mistake. Bottom line is for anyone who spends a lot of years hunting, something is going to wrong at some point.
Good on the hunter for taking responsibility for his actions and doing the right thing. Meat from accidental shootings gets donated to disabled people, so it won't go to waste.