If only that were the case.
See (for example) this and this. And that's just the kids, never mind the recent case (on here somewhere?) of 'bra-carry'...
Law abiding citizens are also part of the problem.
It's a strange thing, this "right to bear arms" idea. It resembles religion closely, as in that reason has little to do with it.
The two stories of children shooting children you linked to give clues that it's not just the legality of gun ownership that is at stake, it's also the lack of responsibility some owners show to ensure their precious guns are, and stay, locked away safely. Parents who let 'loaded guns "just laying on the floor"' ought to be locked away safely as well.
Why one would want to give a 5-year-old a .22-caliber Crickett rifle as a present I can't imagine. Just to give an idea what we're talking about:
(I nicked that image from http://www.crickett.com/crickett_22_LR.php, proud manufacturers of My first rifle.)
Oooh, pretty!
ETA: I have a marketing suggestion for those creeps:
regards,
Hein