But here's the thing - plenty of other countries have full access to all these video games, movies and even their fair share of mentally ill.
What they do not have is constant mass slaughters like this, and that's because they don't have the guns-are-toys mentality we do and open access to as many guns as you want, as powerful as you want, without tracking, liability or lack of social pressure to stop.
Sadly nothing will be done and in a decade we'll have a mass-killing anniversary for every day of the year and everyone will just be desensitized. Instead we'll have armed guards at every place where more than 10 people gather and like the TSA everyone will say "oh well, what can you do".