Let's again try tackling this issue logically.
Let's say we have one violent criminal, and one gun.
If we destroy the one gun, then the one violent criminal can NEVER use that one gun EVER AGAIN to commit gun violence.
If we eliminate that one violent criminal, that one violent criminal will NEVER again commit violence IN ANY FORM.
Obviously, if the goal is to reduce violence as a whole, you work on eliminating that one violent criminal.
If the goal is just to remove that one gun, then you focus on that one gun.
One goal has far more of a positive impact on society than the other one does.