Yes, desensitization is exactly it. I'm 19, so as a teenager I'm around people who enjoy Modern Warfare and similar games almost to the point of obsession, and it disturbed me when I overheard students enrolled in the JROTC program expressing how much they want to get into combat and fire a gun at someone. Perhaps I'm wrong, but I've always been under the impression that men fought WWII for matters that could decide the fate of the world, yet now it seems like a certain amount of kids want to enlist so they can experience all the things they saw in Call of Duty. I can imagine that the realization of war is immense and psychologically overwhelming, yet I can't even begin to think about how much that realization can be magnified if you are first under the impression that you are immortal and that killing is no big deal.