"We do not know why the soldier killed the puppy, but we think that it is for fun. I think that killing has become so ingrained in the psyche of that soldier that he simply cannot differentiate between killing and killing. Note the reaction of the accompanying soldier, he simply says "oh that's mean". Judging from the reaction of the guys on the board, this is not "normal" behavior either."
Yeah it could be the case that the training and stress has turned these guys into sickos.
You definitely could be onto something and this could be the reason.
Alternatively though you have to keep in mind that once a war gets rolling a lot of socios and general sickos decide it would be great fun to join up and see what they can get away with under the cloak of "being a hero for the red, white and blue".
You have to keep in mind natural born sickos like this want to kill and get away with it, they want to abuse animals and torture people and not have anyone tell them its wrong or stop them and throw them in prison or a mental institution for the criminally insane where they belong and what better time and place to do this and probably get away with it then in a chaotic unjust war they reason?
Its sociopathy 101 ie put on the mask of the good guy that society believes in, then do all of your evil deeds under the cloak of normalcy and heroism and if you are caught blame it on stress or combat craziness or whatever.
Ultra far right neocon fascist crazies (like some of the kids in this thread) will buy the sociopath's tale of woe because their mindset is the same as the sociopath's and they don't see anything wrong with the sociopathic soldier's behaviour as a result.
While conscience possessing true republican conservatives ie the real members of the currently hijacked republican party will be horrified and demand the soldier be removed from the combat zone and punished accordingly.