I agree that it is the parents responsibility. I grew up in a house with guns and they were not loaded and didn’t need to be until we were going to go shoot them.
I am curious how you explain to a one year old not to touch a gun....loaded or otherwise.
Being a good parent with loaded guns entails a certain level of common sense. The gun(s) should be at least in a location that your average 5-6 year old or younger cannot reach. Examples: gun cabinets, closet shelves, top of book shelves, concealed in night stand drawers etc... I in no way advocate having weapons lying on coffee tables, on top of items in a night stand drawer and the such.
Our toddlers had no access to our room via baby gates and we actually had a half door on one room.
That said you start training them early on similar to handling hot kitchen items by utilizing negative reinforcement until you recognize an a state of cognizance starting to appear. Couple that with realistic tv and game access where shooting and death are not in the realm of fantasy.