[WS:] I said it is less likely to happen in cultures in which guns and narratives glorifying them are less common. The US is not the only country where both are common. So things happen everywhere, but in some places they happen more often than in others. And if you peruse the tables that you quoted you will find some countries appear more often than others and also that certain occupations, such as ex soldier or ex police officer feature there rather prominently. Also the means by which most of those acts were committed - most of them are firearms. If anything, this shows that access to firearms is a factor here.
I also disagree with your and Jordan's characterization of these events as 'aberrations.' By the same logic, plane crashes are rare, so we cannot meaningfully talk about causes or contributing factors - which is nonsense. Rare events have causes too, just just cannot be investigated by methods that presuppose regular occurrences (such as most statistical methods.) But even statistical evidence can be useful here, e.g. when you examine per capita fire arms related deaths http://en.wikipedia.org/wiki/List_of_countries_by_firearm-related_death_rate The US is on the top of this list among third world war-torn and gang/warlord infested countries. Our northern neighbor Canada has a rate that is half that of the US, and European countries are a small fraction of the US rate. This tells you something, does not it? Mass shootings are extreme events and all extremities are rare by definition, but they are an integral part of a larger pattern.
It is not just the availability of guns per se but also the availability of cultural narratives that glamorize their use. The US is one of countries where both factors are present but not the only one, of course. It is, however, the only developed country in this category. I happen to think that gun control is a mere diversion from a much troubling subject - the anti-social, psychopathic even, nature of the US society. Gun culture is but one manifestation of this, other manifestations involve gut aversion to anything social by a majority of the population, the popularity of survivalist ideology, lack of social services, etc. You cannot blame that just on capitalism as other capitalist countries differ in all those respects quite significantly. Nor is it unique to the US as many third world shitholes share similar features. But something is definitely rotten here and that something comes to the surface with each mass shooting.
-- Wojtek
"An anarchist is a neoliberal without money."