Most American military technology is not very useful for potential opponents. Thats because technology tends to be expensive, and few nations can afford to buy the new stuff (or even some of the older technology.) But there are exceptions, and one of them is wargame software created to train troops and commanders. This kind of software is rather recent, and is designed to operate on PCs or game consoles. This makes the software available to any nation willing to steal it. Many nations have no problem with this kind of theft. This software, like Full Spectrum Warrior, provides a lot of training value at very low cost. Even without stealing the source code (harder to do, but this allows easy modification), nations like China or India could replicate it from scratch using their own programmers.
In particular, low level combat commanders would become better at their jobs with software like this. As a result, these squad, platoon and company commanders would get better at their jobs, and reduce the losses in their units during the first few times they are in combat. While the stolen software is virtually free, the PCs needed to run it are not. But the cost of a few thousand PCs is only a few million dollars. Thats enough to provide adequate training for the NCOs and junior officers of large armies like those found in China and India.