To this and all such similar analogies, sure, anything can be used to kill, but let's talk about only the things whose primary purpose is to kill. Like Guns. Bombs. Canons. etc.

Now one might argue that the "primary purpose" for them is their safety and not killing, but no, it's not. That is assuming safety by creating a 'threat of getting killed' to the opponent.

I know this punishment is little harsh (and should be decided on per case basis based on the level of negligence) - but we should also agree that if there's no punishment whatsoever - this will continue happening. Mass killings is a real problem that needs to be solved, and most of them get access to guns in their mom's drawers or something like that.