I think you interpreted the parent as saying people should be persuaded to support gun control; I think the parent was saying people should be persuaded to oppose gun control. I base this on the "(usually related to smoking, alcohol, and backyard pools)" - the implicit argument being "each of these things kill more people than firearms, why is it the firearms you want to regulate?"
Many parents would rather that their children not visit the home of a friend that had guns in it. Would as many parents be apprehensive about sending their children to a home with a pool? I suspect not.
There may be legitimate reasons that they are treated differently in a way that does not immediately make sense when you examine the risks they pose, but I don't think that choice or lack of it is that reason. I think that you are looking for something more subtle.
Speaking as a parent who has left his children to be babysat at houses with both guns and pools, the pools are a far bigger concern. When both are treated as the dangers they can be, neither is a threat. It's much easier to forget about a pool than a gun, though, and a gun is much less likely to be accessible to a child than a pool. Kids who can't swim can fall into a pool and drown before you realize that anything's wrong, and playing around pools is normal kid behavior, while playing with Actual Real Firearms is not.
I wouldn't leave my kids at any place that I felt was going to be a tangible danger to them - be that a house with a pool and a back door that doesn't have a child lock or pool gate, or a house of an irresponsible gun owner, or a house with exposed electrical wiring, or anything else that I feel poses a material threat to my child's life.
