She called you out, rightly, on your lack of critical thinking.
Also, never apply the theoretical math from an economist to population dynamics or anything inherently biological in nature. You'll end up with egg on your face, every time. Like now.
It's myth that a tribe can afford to lose more men than women. Myth.
It might be mathematically sound as a theory, by life is way too complex for a simple math formula. Time and time again, not to sound too much like Ian Malcolm but he had a point, life beats the math and finds a way.
Especially when said maths come from economists who have reduced human beings down to commodities for capitalist wet dreams.