As I work in the video game industry I will tell you first hand that a lot of video games, especially online games, focus on one set of emotions, that being highly aggressive kill-or-be-killed. Things like compassion, rationality, even sportsmanship are often left by the wayside. I've witnessed countless times the mental state of people deteriorate from general happiness to intense anger and antagonism playing violent video games. Furthermore video games are not the same as film, books or television as video games give a person an active role in the story. Furthermore modern day video game developers often do not bother with things like morality instead choosing to let people act out a murderous rampage guilt free, essentially catering to a psychopathic mindset.
I'm sick and tired of hearing gamers say that video game violence has no effect on the mental state of people. That's a crock of shit. Any emotionally mature person with more than two brain cells to rub together can see that running around in a video game killing people for hours on end, day in and day out for weeks, months, years can take it's toll on the human psyche.
Now I am not saying that violence doesn't have it's place in video games, rather that there are far, far too many games focused on nothing more than people running around trying to kill each other. I am saying that video game developers and publishers for the most part just want to pump out what they think will earn them the most money and if that means catering to people's lowest most carnal mindset then so be it.