"WHAT ARE THE GUN GRABBERS THINKING
if NOT that?"

 I don't know anyone that wants to eliminate all guns from all persons nationwide.  Can you reference anything where someone is pressing for legislation to remove all ownership of firearms for all US citizens?

 Theoretically if there was a person who wanted all possession of all firearms from all US citizens then they may logically think that the removal of all firearms from the US including law enforcement, military, criminal organizations and other nations capable of transporting weapons to US citizens would then result in less criminals having guns.  

 This of course would include the stoppage of all gun manufacturing in the US, and some sort of corrective action for wildlife controlled by  hunting practices, perhaps mass capture and euthanization, or some other control feature.

 

 Its to me the same level of absurdity as saying gun grabbers think fewer criminals will have guns while not providing a single source of information making that assessment credible.

 Nobody I know that is pro-gun control wants all guns banned, and none think that criminals will have less guns.  I'm sure these people exist, yet that does not change the fact that I do not know of any.

Perhaps because there are quite a few accidental killings every year by kids getting hold of weapons or people shooting themselves with unsecured hand weapons? Or young people going crazy and grab dad's gun and start shooting teachers at school?

Basically, not all are fit to have a gun.