Kids don’t spend 100% of their time at home. They go out in public, they go to friend’s houses, they go to parties. They will, 100% of the time, find themselves in situations where irresponsible people are making decisions. Your job as a parent is to equip your children to navigate an unsafe world.
In some places, that means knowing what to do if you stumble upon a black bear on a trail. In other places, it means knowing what to do if you find a little baggy of white powder on the ground. In the United States, it means your kid should know what to do if they find a handgun in a bathroom at a truck stop while out on a field trip. That is not a situation a parent can prevent unless they are constantly hovering over their child. It’s never likely but it can happen to anyone.
What would be irresponsible is not teaching your kid these skills so that they have to figure it out on their own, especially when they don’t understand the seriousness of the situation.
Again, 450 MILLION guns. You can ban them all today, even if everyone agreed, we would be pulling guns out of cellers and closets for the next 100 years. “Ban them all” is not a thing you can just do. That would require a constitutional amendment, one that basically one supports, so good luck with that.
“Anywhere a kid might go” is literally every public place. Concealed carry is not outright banned in any state. I support pretty heavy requirements for concealed carry, but even an outright ban would not prevent this. Even so, most states have very loose requirements (or none at all) and there’s basically no political will to change that.
Teach the kids about guns. This isn’t even a political position, this is a very straightforward policy to mitigate risks that presently exist and are not going away any time soon.