There are many explanations:
— the murder rate dropped because of the legalization of abortion (which I am not an advocate of): 20 years laters, all the father-less unwanted babies by evil mothers were not there to kill.
— the progress of medecine: many things that were lethal decades ago can be cured now.
http://johnjayresearch.org/wp-content/uploads/2012/04/databit2012_06.pdf
It’s not just demographics - the rate of arrests for murder by perpetrators aged 15-17 dropped by 66% from 1993 to 2000, and the rate for perps aged 18-25 dropped by 40%; both rates have slowly continued to decline since.
Given that the introduction and growing popularity of, realistic looking FPS games with splattering blood EXACTLY matches the steep decline in the murder rate by people under 25, wouldn’t you agree there’s a BETTER case to be made that FPS games PREVENT murder, rather than cause it?
And keep in mind that for men under 25, right now, large amounts of FPS gaming is universal- that is, today, literally EVERY boy/young adult from the ages of 10 to 25 plays a lot of violent, bloody FPS games.