A rifle was essential in colonial America, as game was an important part of nearly everyone's diet.
If someone owns 200 cars he is a "car nut", If someone owns a trunkful of pancakes, he is a "pancake nut", and if someone owns 100 guns he is a "gun nut".
Not everyone with 100 guns is likely to run out and shoot suspicious Negroes, but the 100 guns will eventually be lost, sold or stolen, and the more guns are in circulation, the likelihood that someone will be shot with one of them increases. I once tutored this French Canadian sailor in English for several months. He showed me his gun collection once, He had over 100 of them, a trunkful of rifles and shotguns, a large suitcase full of pistols. None of them was registered. A month later, someone broke into his house and stole all of them. So even though he was a stable and normal person, the odds are that some of those guns surely were used in some dangerous and/or illegal way.
It may be a constitutional thing, but it is still not a good thing when many more guns are put into circulation.