I wasn’t disputing that it happened.
Robert van Tongeren
1

Fair enough but that is just one report. There are similar reports from Sweden, Ireland, UK, France, Japan and Australia. Add to that the awareness that it makes sense (the fact that there has been a LARGE increase in teenage teenage violence in recent years), and I would not dismiss it. Something has to account for teenagers who are not Muslim, who have no strong political or religious affiliations deciding to join ISIS. It has happened with disturbing regularity, and from all manner of backgrounds and from various countries. The single commonality is an obsession with games promoting violence. I would be more than interested in considering another plausible cause.