Organized mass killing efforts are unstoppable, but emotion driven ones are amplified by the lethality of easily available weapons and people's experience with them. Meaning that all this culture of having guns, playing with them, knowing how to use them is the reason mass shootings can happen. You can't shoot lots of people with a kitchen knife if you suddenly get passionate and emotional about killing people.

Except Americans have ALWAYS had extensive access to firearms, but frequent massacres by emotional hotheads are a fairly recent problem. In the 1920s you could buy a fully automatic Thompson sub-machine gun via mail order. People weren't shooting up schools regularly, and the worst massacre in the 1920s was done with explosives. Access to weapons hasn't really changed, so what has changed about the American PEOPLE?

My guess is - it was naturally suppressed in the past since there was only top down, centralized, slow and spotty in reaching audiences mass media and recently internet freed it. Everyone with a smartphone became its own little mass media, able to easily find like minded people, supercharge hateful propaganda through feedback loops. Who is spreading that propaganda and why is another question though. Anyone from politicians, foreign, local state actors to gun manufacturers.

AUM was 1 attack 24 years ago. If you sum that and KyoAni, you end up with something like 50 victims in 25 years.

Do you think these numbers are even remotely comparable to US ones, where there have been hundreds of incidents only this year?