Also, while even some of the best educational software (like Duolingo) have problems, they’re generally not the problems that the authors expected.
The discourse around Mathematica, educational software, and video games has changed a lot in 20 years. I've the whole thing, not much is particularly relevent. Wolfram asks simply too much per license to be widely used in primary and secondary education.
In addition to the military training the book also talks about dis-association of killing through different methods and how that increased the "shoot to kill". The basic argument is that it is easier to kill someone when seeing them at a distance through the scope of a rifle than being right next to them and stabbing them. The other part of the dis-association is campaigns to dehumanize the enemy in war and not refer to them or acknowledge that they are individual humans.
The video games argument in "On Killing" isn't part of the main thesis of the book, it is more tacked on the end. Whereas the rest of the book is looking at the past and evidence of what has happened. The video game part of it was (at the time) more focused on current feelings and attitudes towards it and was not substantiated.