If nuclear weapons were outlawed, only outlaws will have nuclear weapons. Therefore: Everyone should have nuclear weapons. Problem?
You are poorly failing to compare a weapon with less than 600J of energy to something with 4.184×10^15J of energy. You are equating the power to kill a few people to the power to eliminate a large metropolitan area. This is the same as asking if it were ok to drop a grain of sand on your head or 200 empire state buildings.
You can't buy a nuke on a walmart shelf like you can a gun (behind a glass case, whatever). Anybody can get and operate a gun, I would go as far as to say that ALMOST anybody could even make a rudimentary gun with simple hardware store parts. You cannot do this with a nuke.
Ever heard of the cold war? Mutual destruction? Every country with any significant power/interest in wold politics/commerce does have nuclear weapons. Nuclear weapons are essentially outlawed with all of the regulation. We try very hard to not let those outlaws get the technology to build weapons of this type. We also try very hard to prevent unstable government entities from getting nuclear technology to prevent the sale of weapons like this to outlaws.
This man has a drivers license! Lets give him his own Airbus A380!
Don't take it too far. Your analogy creates a slippery slope. Problem?
Kleeneness is next to Godelness.