The rise in violence has many causes. I think about the 1980s, when there was no internet and there were no such realistic games as now. People lived in a different world and domestic murders, as a rule, were among alcoholics and those who fell out of the normal social circle. I think that now, decades later, people have become more lonely - and therefore more distant from each other.
I don't think it is gaming, but the disconnection from people through gaming can have an affect, since the alternative is also disconnection through social media, or disconnection through streaming content. The disconnection is the main issue I believe.