If you bring up something about American men defending America, be prepared for a response along the lines of, "If men weren't trained to kill, there would be no need to defend America," or "If Nazi men weren't trained to kill, Jews would not have been under threat." There might also be a strong insinuation that men are by nature violent, not just taught to be violent, and that women are naturally peaceful.
If you ever do something like this, it would be good to have at least a partial list of female rulers throughout history who were war mongers. Just be prepared for some sort of response that they wouldn't have been war mongers if they weren't driven to it by men or the patriarchy.
Trying to plant seeds of doubt might be much better than being confrontational. Remember, though, that she will control the forum, you're unlikely to get any facts through to her, and you'll be surrounded by her fellow travelers.