Re: Shooter games
"Otherwise it would not be necessary to put "do not kill" as a rule for tolerant societies and include it in Bible etc."
The Ten Commandments cover the behaviour that is likely to disrupt the social cohesion of a small tribal group. The laws in Leviticus allow, and even demand, the killing of those outside that tribal group - or its members who do not conform to the tribal laws effected as religious dogma.
While a mob of any size can often be incited to mindless violence - many pastimes are societal safety valves to channel that aggression, often vicariously, away from disruptive conflict.
Steven Pinker's book "The Better Angels of Our Nature" (2011) explores the nature of violence in human societies and argues the trend has been towards reduction. He does attach a caveat that the trend is reversible if a society's general culture becomes intolerant and less educated.