"Anyone who would argue that drugs should be legal must certainly recognize that making them illegal has had little effect on their availability. So why would making guns illegal be any different?"
It's a very sensible question and one that deserves to think of it.
There's an obvious difference, tough: drugs produce ill people that *need* more of it, guns are not the same.
Another one is the very different industries needed to fill the streets with drugs and guns: it's much easier for the former than the later -while this could change if 3d printing stands after its promises.
"If anything, we could expect it to fuel a black market"
Quite true and a difficult issue to deal with in a (modern state) representative democracy with politicians only interested in next campaign.
Difficult, but not impossible: Europe is (comparatively speaking) free of handguns but that was not the case after WWII, which means it is doable.
"I just get sick of this paternalistic notion that government is somehow obliged and/or has the ability to keep us all safe from each other."
You also have a point on this. But your flaw, I'd say is considering government is something different to citezenship. It should be not that government is there to protect each other but that each other empower ourselves through government to have the kind of society we want to live in. And I certainly, while not at any cost, want to live in a society where I don't need to be worried to be killed by a handgun.