Anyone can get a gun, I bet you in about an hour I could get one if I had cash, especially if I livrd on the Mexican boarder. This why gun contol is a foolish idea.
I do however agree that some people when armed are extremly dangerous and should not be allowed to own one.
The main reason why the Constitution allows gun ownership is to give the people a way to fight an out of control government and up hold the rulings of a Constitutional Convention, which would erase the authority from the federal government. The States would run the Federal Government til new leaders are elected.