For the most part, I'm with you. The gun is there to take care of me and my people, not the car. There may be times when I have to take it with me. I want it to be portable, and safe if tucked in a waistband without a holster.
I would want any loaded gun in the vehicle to be "drop-safe." A T-bone collision (if the gun's muzzle rides laterally) or a car going airborne and then hitting the ground hard (if the muzzle was vertical) could impart great enough force to cause an "inertia discharge" if the gun was not internally drop-safe.
I can see the person who perceives a need for a long gun in the vehicle to have one stored there. Note that from hunters with guns in pickup racks to cops, the long guns tend to be carried with empty chambers.
Leaving a lethal weapon in an unattended motor vehicle is never the greatest idea -- and is illegal in some places. That said, an individual's need to have it there -- to shoot coyotes that prey on his sheep on the farm, or to fulfill his duties as a police officer, or anything in between -- can take precedence over that. Each of us has our own set of needs to balance against our own set of responsibilities.
And, of course -- EACH OF US HAS THE RESPONSIBILITY TO KNOW WHAT IS LEGAL IN THE JURISDICTION WE MIGHT BE IN!