You generally have a point but

and all three of those things being assumed as the only roles a woman would play in a war is just gross

??? Cooking and first aid are normal things for volunteers to do, male or female, it’s not that she’s a woman, but women seem to mostly have the good sense to not fly halfway around the world to get blown up as soldiers like some functionally-suicidal men did, even though there are certainly women on both sides of the war in combat roles.

There are some other normal volunteer roles, e.g. sanitation is very important, but you’d surely say the same thing if people were commenting on her not pursuing that (“oh! so women should be cleaners?”). Anything beyond that, like being a mechanic or nurse or something, requires a serious level of training