It's not just my personally owned guns that I want to protect my children from (my guns are stored away, without ammunition), it's those owned by others.
If you don't own or use guns, how do you want to teach your children their use? The only thing I can say then is: "Don't touch them! Be careful if other kids play around with them! Tell me if they do!"
From my perspective as a German citizen, there aren't many neighbors with guns that I would need to worry about. Maybe in the US it's different enough to make gun handling customary. It's not here.
But if I was a gun owner, I had a different relationship to guns. They would be part of our life, and the kid would recognize them and get curious about them. ("Why does Dad never let me use one of them?" "Hey, friends, Dad is out, but I know where he hides the keys to his weapons locker! Wanna try?")
I wouldn't want it to accidentally figure out how to get hold of it and use it carelessly (or just ignorantly.)
If you teach your child, and make visiting the shooting a special parent/child event, it has a different type of respect to it.
Well, at least that's my ivory tower theory on children education. I don't have any and I might be totally, utterly wrong and my children would become nightmares... We might never know...
For instance, do you still educate children on the danger of drugs even if you don't have any in your house?
Well, I certainly won't train them in drug use or teach them how to build a bong or anything.

I will do what I'd do in the gun case as a non-owner. "Don't touch them." And if neccessary and approrpiate, expand on this lecture to make them understand why they shouldn't touch it.