They do? Last I heard they were just using America's Army to train.
They are using games to "break" the hesitancy to pull the trigger.
They are using video games to train, and not just America's Army.
They're using the Sims to show the troops to wait until the enemy washes their hands before they attack, because that'll keep the enemy occupied for at least a half an hour. They're using Warcraft to teach how every engagement should begin with the troops building a house, and sending a platoon or two out to mine for gold and chop down trees. They're using xtreme Paintball so that if the troops are captured they'll know that even if the enemy cuts off a finger or tortures them, it still can't be as bad as playing xtreme Paintball. Plus they're using Katamari Darmacy to train the Army how to use giant balls to roll up and capture enemy troops. And tanks. And cities.