Number of people killed this year by mass shootings, according to that article this year: 462
Car accident fatalities per year according to this article[1]: 30000 (500+ per week) .
Low end estimates of flu deaths per season [2]: 3000
These latter two are not anything you would worry about significantly (they are not particularly likely to kill you). Why should I care about being killed in a mass shooting?
[1] http://www.iihs.org/iihs/topics/t/general-statistics/fatalit...
[2] http://www.cdc.gov/flu/about/disease/us_flu-related_deaths.h...
Yes, if the people and governments were less emotional, we could probably avoid lots of deaths. However, let's not forget this isn't a matter where you can have only one thing. Researchers can improve cancer tratament while mechanic, civil and traffic engineers can reduce accidents. I'm not sure who's more qualified to reduce shootings, but we should also look into that.
These events aren't exceedingly rare. Quite the opposite. In fact, the San Bernadino shooting wasn't even the only mass shooting in the US on December 3rd. IIRC, there has been one mass shooting, on average, every day since the Sandy Hook shooting in 2012.
More info: http://www.npr.org/sections/thetwo-way/2015/12/03/458321777/...