Read through those articles briefly (will read them in more details when I get home).Firstly, the studies do attribute the increase in aggression to media in general, and TV in a few specific cases.
Second observation; the last article
http://www.apa.org/journals/psp/psp784772.html
seem very biased. How is the study done!? The details of the study were very brief, only the "conclusion" was printed and then went STRAIGHT TO linking violence in video games to school shootings.
I felt the first three articles were interesting reads, but the last one was very scrapgoat style.