but they have to prove their need
No. They should have to prove their competency. Need is too easy to dispute. We dont get to dictate why someone needs a gun any more than why they need a car. If they want one, have the means, and demonstrate compliance with safety guidelines, then they shouldn't be denied. Canada handles this fairly well.
School shootings demonstrate why some people should absolutely be denied access to guns.
The current US political situation demonstrates why more people should arm themselves.
Right. Like, can you imagine what society would be like if we let bald people vote? /s