You could use that argument to say there is no need to own a car that will go 100 mph. In my town, and probably the entire USA, I understand there is not a gun of any kind to be bought anywhere. Corona virus fear. I guess that is the same thinking that has people buying a years supply of toilet paper, though I would feel safer during a social unrest with a gun in the house than a years supply of toilet paper.
I do not fear machine guns. The Vegas shooter could probably have killed the same number of people with a semi-automatic. He was shooting into a crowd that could not escape. There will always be sociopaths that kill strangers. They drive cars into crowds. They poison Tylenol. They fly planes into buildings. They cut peoples throats. They rape and kill children, sometimes their own children.
You are free to not own a gun, or a machine gun. If you dont own and or carry a gun, feeling that luck, and or the police will protect you, good for you. I wish you luck. I though, feel a person should rely on them self;
I live within my means.
When I had children, I bought life insurance on myself and their mother.
I drive a 30 year old car.
My wife drives a 12 year old car.
I am my plumber, auto mechanic, electrician, financial advisor, HVAC tech, and lawn maintenance man.
I have no illusion that Congress, or the police will protect me from sociopaths.
I believe one is responsible for ones self.
I own guns. In the unlikely event someone kicks my door in, I have the option of pointing a gun in their direction. If social unrest comes, and I fear it will very soon, I am glad I live in a country where one can own guns.
It is inarguable that a bad person with a gun can only be dealt with by a good person with a gun.