Its obvious we all have had different experiences with both guns and life, and it appears many seem to have led pretty sheltered lives too.
Being older, Ive seen a lot of things change over the years, and in a way I really dont consider good. Not teaching kids young about discipline and responsibility, are a major sore spot. Its up to you to teach your kids, and not rely on others to do it for you.
We grew up in a rural/military environment and were constantly exposed to all sorts of things, including all sorts of guns and explosive things. We also were loaded up with responsibility at a very young age. I had my first "money making" job at 10.
I saw that one negative comment about a 5 year old driving and really had to wonder. Just about everyone I ever knew, grew up in our dads lap, steering the car from even before 5. My kids did the same. I learned to drive a stick driving around our neighbors farm in my dads old VW bug at 10, and was quickly driving it by myself once I had it down. I had already been driving tractors and other farm equipment before that. I taught my kids to drive a stick around the same age.
We learned to shoot around 4 or 5, just like our kids. We were lucky enough to have access to all sorts of stuff too. I shot my first SMG at 8, an M3 "Grease Gun". Shot it a lot too, and could never get enough. I was instantly hooked, and never got over it. Shot a lot of other "cool" things before I was 10 too, including belt feds. Both or boys were shooting my MP5 at 5, and by the time they were 10, had shot (and could shoot them well too) more full auto guns than most adults have ever seen.
My experience has been, "most" adults have never seen or held a full auto gun, let alone shot one. Of course, everyone is an expert on how dangerous they are in the hands of children.
I will say, that boy who let that girl shoot the UZI, was wrong, and simply because the choice of weapon was inappropriate, and his teaching skills were poor. Not because it was a machine gun. Anyone who has shot one of those type guns, UZI, MAC, etc, understands why too.