It’s not just parenting. There are crap parents worldwide, yet this only regularly happens in one place.
E: downvote all you want. Remove my comment if you want. You know it to be true. This is a US thing. Stop worshiping your guns.
And if you are to have them, keep them in a safe, inaccessible to children, when not in use. The fact that this is a controversial statement to Americans is insane.
You can’t just handwave away gun problems as “oh it’s the parent’s fault, nothing can be done”