Men have been constantly culled en masse so they're selected for cooperation at war. Women only failed to individually reproduce if they weren't sexually attracted to the invaders that killed the men of her tribe. This has obvious consequences.
It shows up everywhere - women find men with foreign accents sexy since her lizard brain concludes that if he's identifiable as an outsider and is alive he must be a conqueror. Women want to stop and ask for directions b/c they don't care if they advertise as outsiders.