UnEndemic

Yes. As a matter of fact we could. We could also regard them as the work of hostile extraterrestrials. Both would be equally accurate.

"Mass shootings" in the United States aren't "an endemic local health hazard." They're rare, but splashy events that capture both widespread media coverage and the public imagination, and in some sectors (especially the urban Left), spark moral panics. They garner nationwide attention precisely because they happen in places where "middle-class America" expect to be "safe," and this is what triggers the pearl-clutching and political grandstanding. The seemingly random nature of them, and the fact that the ones that attract the most media coverage are in places where such violence is unexpected by the middle-class public leads to a pervasive sense that lethal violence can happen anywhere and at any time. In other words - It could happen to you, and there is nothing you can do about it. And when outlets like The Economist describe this particular subset of gun violence (95% of homicides in the United States have only a single victim) as characteristic of or prevalent in the United States it enhances that sense of ubiquity. It the regularity of coverage of "gun massacres" (and the loaded terms used to describe them) that breeds familiarity. And this is not intended as a criticism of "the media" per se. The United States a large country - for me to drive from my apartment to the home I grew up in is a longer drive than Amsterdam to Ankara - and I'd still have half again as far to go to reach where I spent my Freshman year of college. It's impossible for me to familiar with what goes on the vast majority of the United States without people compiling and presenting that information in public fora.

If one uses the same definition for "mass shooting" as is commonly used for "mass murder" (four or more people) they're pretty rare. To be sure, this doesn't account for the number of people injured, but the numbers aren't as high as many people think they are. Source: http://www.bjs.gov/content/pub/pdf/hus11.pdf.

To be sure, the United States has a very high homicide rate when compared to the rest of the developed world, being very near the top of the rankings. The third world, however, leaves us in the dust. And, as an aside, in those United States territories that have third world rates of homicide, killing seems to be purely a local matter - the broader national media rarely mentions it. And it is this comparison with the developed world that drives the expectation that the federal government could effectively eliminate the problem if only it had the political will to enact the correct curbs (or outright bans) on individual firearms ownership. While it's true that if one could eliminate all of the homicides carried out with firearms in the United States, that our homicide rate would look more like that of Great Britain, it's highly unlikely that even a 100% effective firearms removal scheme would leave people with violence on their minds with no other outlet to carry it out. Dedicated weapons may be frightening, but they are not the only possible way to kill someone.

But more commonly, many top police officials say they are seeing a growing willingness among disenchanted young men in poor neighborhoods to use violence to settle ordinary disputes.

“Maintaining one’s status and credibility and honor, if you will, within that peer community is literally a matter of life and death,” Milwaukee’s police chief, Edward A. Flynn, said. “And that’s coupled with a very harsh reality, which is the mental calculation of those who live in that strata that it is more dangerous to get caught without their gun than to get caught with their gun.”
Murder Rates Rising Sharply in Many U.S. Cities

It is unlikely that the honor culture that exists in the inner city would be short-circuited simply by curtailing access to firearms. And it's not the only driver of lethal violence in the United States. Compared to the everyday, mostly poverty-driven violence that claims about three dozen or so people in the United States on a daily basis, mass shootings are a blip - it's roughly comparable to the homicide rate from domestic violence for men, a statistic that most of feel is small enough this it's not worth paying any attention to. It's likely that we'd save many more lives with a more equal distribution of income/wealth and better access to support services. Given this, it's likely much more accurate to say that in the United States that poverty is the endemic local health hazard that the county is incapable of addressing.  (But somehow the regularity of poverty in America has apparently yet to breed familiarity with it.)

But since most of the people murdered in the United States are in poor and/or minority neighborhoods, they are out of sight and out of mind. Given the legal obstacles to the sort of sweeping restrictions on personal firearms ownership that people call for in the wake of these incidents, we're better off working to stop the constant everyday killing that happens in our society by addressing its causes, rather than its tools.