I skimmed through the paper and they used a punching bag for venting out frustration. I think that and video games are fundamentally different. Punching bag do not give you a sense of objective fulfillment which video games do. Also video games generally have group dynamics, even in quite a few of single player games. But agreeing with you on the broad point, other research papers do suggest that violent games increase aggression. Although another interesting link(http://www.huffingtonpost.com/2014/04/08/violent-video-games... :the actual paper is behind a paywall) seems to suggest that it is not violence but our failure to master the game play that causes anger.