What's the point in sending the females of a physical combat-based race away in a situation like this if both genders have the same muscle mass? It's one thing for them to exhibit the less physically confrontational behavior we see in human females due to innate psychological differences in day-to-day life, but it's just plain dumb for them not to even come to the defense of their home when it's being shingeki'd by a kyojin considering it wouldn't really be a good survival strategy for a colony-based species to eject their combat-capable females when facing sticky situations, significantly reducing their chances of survival in exchange for what, a monogendered group incapable of parthenogenesis remaining somewhere out there in the wild? It might kind of fly if the orcs had swarm-like numbers and/or some pheromone or magic-based means to find other colonies, but as it is, it's very unlikely for specimens that exhibit this type of behavior to efficiently pass on their genetic material to the next generation.
Or maybe I'm in far too contemplative a mood to be reading this right now if this is my reaction to a throwaway phrase in a manga not really written to fulfill anything resembling satisfaction on an intellectual level. It was fun to sperg out though.