Well....to borrow a couple of sayings - the horse has already bolted, and it is pretty hard to put toothpaste back in the tube!
The main difference in military training between WW1, WW2, Korea, and the later more effective training for Vietnam, was primarily "systematic desensitisation".
Earlier training involved shooting at fixed static targets - bullseyes and the like.
When soldiers hit the front line - shooting at live humans was still going against everything that society had raised them for.
The vast majority of soldiers would not shoot at the enemy - even when faced with rapidly approaching fixed bayonets!
Later training involved reactive targets shaped to resemble the enemy, with contact drills being rehearsed until the response is automatic - so the soldier doesnt have to think - he just reacts as his training dictates.
Modern video "war-games" use the same principles as modern military training - constant repetition so reactions become automatic - leaving no time to think about consequenses.
======================
There is so much money to be made flogging [violent] video games and movies, I cant see much chance of limiting access - and the boundaries of these games and movies are getting pushed further every day.
Could you imagine something like Game of thrones, the SAW and Wolf Creek movies, or the many military style video games being as easily available in the 1950's or 60's or 70's?
As a kid, I thrived on a diet of TV shows like Combat and Spyforce, movies like Reach for the Sky, Hunt the Bismark, Twelve o'clock High.
Rainy day reading was generally stuff like Purnells History of WW2, The Desert Column, [and the entire catalogue of war comics

].
I have a strong interest in military history and a healthy respect for firearms and weaponry, a lot of gratitude for the soldiers who use them - and I am truly thankful that I have never needed to use violence to solve a problem.
What worries me is the amount of kids - and adults - who have developed a very short fuse.
"Modern" movies and video games are not helping.
Luckily, here in Australia - small concealable firearms are not as readily available as in the "Land Of The Free", or we might have a lot more damage to deal with.
stephen