Any activity that involves active participation and some form of exciting stimuli (bright lights, loud sounds, threatening things etc) will have some level of adrenaline rush. How the kids (and adults) deal with that, however, is entirely based on their background, what they have so far learned, their culture etc.
I think the reason we pick on kids a lot is because they're young, and they haven't reached the point of maturity, so they still have some "primal" (if you will) elements to their behaviour. Really though, it's all about teaching them. If an adult actively engages with them and teaches them what's right, wrong and so on, then kids will grow up for the better.
tl;dr I don't think media violence is the root cause, but is one potential method to reach one potential outcome based on the individual and their experience