That's not how statistics works. "Not all drunk drivers kill people" is a bad argument because drunk drivers are way more likely to kill people. Same thing with crime. If you're arguing that his shitty situation isn't the main reason why he resorted to a killing spree, then you kinda have to argue the same thing for all crime, and there's research that disproves that logic for various forms of crime.
Have people considered NOT murdering other people? Ohh wait, most of them have. That's why most of them don't. Ahh silly me.
That's not how statistics works. "Not all drunk drivers kill people" is a bad argument because drunk drivers are way more likely to kill people. Same thing with crime. If you're arguing that his shitty situation isn't the main reason why he resorted to a killing spree, then you kinda have to argue the same thing for all crime, and there's research that disproves that logic for various forms of crime.