Makes sense to me. I think it comes to down to the greater good. The majority of gun owners are responsible I'm sure, but like you say it's a numbers game. The more guns going around mean a higher risk of people getting shot. So those responsible gun owners need to make a sacrifice, for the greater good.
It's like justifying driving a big 4WD because "it's safer". But safer for who? For the driver maybe, but what about everyone else on the road? It's putting your safety above others, which is not civilized.