Well, here's the thing, even if she is right in her conclusion, her argument, as relayed to us by you, is deeply flawed. I'd rather talk with someone who is wrong, but is capable of using logic and new information to self correct, than someone who is right, but cannot support their claims and is able only to affirm their point with ultimate conviction. If she really is incapable of having a rational discussion about such a thing, then I say you just resort to (mock) misogyny and retort with something like, "do I make a habit of coming into the kitchen and dictating how you make sandwiches?"