I guess I could provide examples on both sides of the issue. I had pellet guns (both rifles and handguns) when I was about eight years old. I even "militarized" the Crossman 760 by sawing off the barrel, removing the stock, and painting the whole thing black. It was concealable, to say the least.
Once, I heard someone on our roof (turned out to be my sister's friend) and when he saw me walk out of my bedroom at 2 A.M. bearing that thing, he raced off the roof jumped off of our garage and nearly shattered his leg. Today, he owns one of the largest battery companies in America.
I used my pellet gun for hunting frogs and turtles down our canal. Once, I even shot my brother in the leg with the dang thing (boy, did he deserve it!
).
Anyway, fast forward four decades and I guess we're now in a culture where pellet guns are considered weapons just like anything else. I'm not sure whether that's a good thing or not. Listen, when I was growing up we used firecrackers and M-80s to perform "demo" missions on my model ships. Dangerous? Of course. But we still maintained a strong level of care and concern for what we were doing. Some people I wouldn't trust with spit wads.
I doubt very much I'd be who I am today if I didn't grow up doing the strange things that I did way back then. I think that "training" should be the realm of the parents and that lawbreakers should be punished (such as a 16 y.o. taking any form of gun to school -- that's just plain stupid beyond everything else).