For 15 years, I have had to defend video games any time someone goes out of there way to make a public spectacle declaring they're the reason for some violent act. 

And while yes, they can be used as a tool for influence, someone doing something horrendous is just that: SOMEONE DID IT. Not a video game. 

 

And please note; while i did complain about lack of parental supervision, parents are not the only group of individuals who are capable of teaching, supervising, and inspiring. Food for thought.