“Second, those FPS games are military techniques applied to transform a normal being into a brainless killer, a sociopath.”
Ummm....no. Either you’re born a sociopath or you’re not.
While there's a big genetic component, the best way to create a sociopath is horrific, continuous child abuse at a young age.
And there's also a pattern of a lot of serial killers having had a severe head injury when they were young, as well.