If I took a navy cook, put a rifle in his hand , and gave no additional training is he a marine or be called a Ranger? But they are all military right? That’s a better comparison to illustrate my point .
Maybe that's the difference. In the Military you are trained to be a soldier first, then your specialization. So yes if you hand that cook a rifle he is going to know what to do with it and most units have to qualify with a rifle every year.