The thing is, a member of the military does not have to go off to war. They can desert, they can fake something, they can injure themselves, they can maybe just resign or muster out, they can even suicide. Not great choices, with varying levels of dire consequences, but still a choice.
A Queen of the fae has no choice. They have some flexibility in their actions, yes, they're not automatons. But they cannot choose not to do those things. There is no choice allowed.