Mr part deux: I confess I don't understand the fire extinguisher analogy.
One of the problems we are trying to combat is gun trafficking, the movement of guns from good hands to bad ones, especially en masse for money. The Justice department notes that over 220,000 firearms are lost or stolen each year. Many of these do end up in the wrong criminal hands. While most of the gun trafficking is done by corrupt FFLs, there is a smaller percentage done by corrupt gun owners. Like cars, boats, ATVs, motorcycles, planes, precious art, if we can track where specific guns are going, we can slowly shut down the individuals and the conduits involved in trafficking. As I've said before, criminals aren't getting their guns from liberal gun haters; they don't own guns. The thugs that people rail about are getting their guns from us, the gun owners. We bear the responsibility of trying to put a stop to it. For instance, the narcos in Mexico get 75-95% of their guns from the US. As gun enthusiasts we share the responsibility of trying to shut that down.
A side effect of tracking gun registrations is personal responsibility. If I know a particular weapon is attached to my name, I will attend properly to its care and storage.