السلام عليكم ورحمة الله وبركاته Im interested in why its the case that shirk in video games is haram upon the user but for example in shooting games killing, or stealing your opponents loot or things like this dont prohibit the game. (I dont play shirk games I just want to understand)

The difference is that kufr and shirk are kufr even in play. A Muslim must reject shirk at least in his heart, so how can he allow it, or even watch it, and take part in it for the sake of a game! Play something else. As for fighting or taking loot in a game, it is not the real deed, and the asl (the default ruling) in games is that they are permissible unless they contain something forbidden, so such a game is judged by what it actually contains.