Meh... you can only take that logic so far. Certainly people can be trained to shoot others. Certainly people can be trained to be violent. But video games aren't a very effective training tool in this instance.
I play/ed all kinds of games growing up and now and I detest real world violence.
It's a serious question, since magazines, politicians, web sites, other talking heads say that video games cause us to be violent motherfuckers.