I'd like to avoid sparking off the conversation about what kinds of arms should and shouldn't be allowed, or the problems of proliferation of arms in civil society. I have nuanced views on it that are frankly boring and off-topic here.
But, as long as pretty much everyone in the US has a right to bear arms, and simple and easy access to weaponry, I say the very least we can do is teach children (and adults) firstly: to not touch a firearm if you have no experience or training with them, and secondly: how to properly handle a firearm in a safe way (eg. trigger and range discipline, and how to safely unload and make safe various weapons).
I don't belong to the NRA, I'm not particularly conservative. If anything I'm liberal. But it's important, from a harm reduction standpoint, to teach everyone how to safely handle dangerous items. There are a hell of a lot of functioning guns in the US, so it makes sense to try to mitigate some of the risk induced by the fact that they even exist.