To kill people. That's exactly my point. People (especially minors) shouldn't be allowed to own weapons/"tools" that are mainly designed for killing.
You sound like an overprotective soccer mom I know. Do you also believe that video games insert satanic ideas into children?
How about this. We ban ANYTHING that has to do with violence. Music, movies, art, toys, EVERYTHING. Nobody will be violent then! But what about stuff like Captain America? Too violent, gotta trash him too. Banning pocket knives is just ridiculous. The amount of deaths caused by POCKET KNIVES has got to be super low. They're no easier to conceal than a small pistol, and more often than not the blade isn't long enough to pierce straight through a human heart, let alone their rib cage. If you want to be anti-weapon, go bring it to the now-dead gun policy thread. A lot of the posts there said that restricting guns MORE would just be a bad idea, with reference to (insert city name here, can't recall, Chicago?)