Banning Ski Masks to Stop Bank Robbery

Would banning ski masks help stop bank robbery?
Of course not! That’d be absurd. Ski masks don’t cause bank robbery.
Similarly, guns don’t cause crime. In fact, they can be used to defend against crime*! Heck, I can think of a whole heck of a lot more fun, useful, productive, and beneficial things that one can do with a gun than one can do with a ski mask. Neither ski masks nor guns cause any harm by themselves — they’re simply inanimate objects.
Why, then, are there so many people who seem to think that restricting (or banning) guns will help reduce crime? It doesn’t make any sense!
* Something that ski masks can’t do. At least not the last time I checked.