The weird part in the story is that the Sabine women are essential in resolving the conflict by convincing the men to make peace with each other. This is kind of weird when this is supposedly an instance of war booty because enslaved men or women would not be in such a position and the Romans or Sabines in no hurry to comply with anything. The resolution of the conflict is not them being returned to the Sabines afterall so it is not really fathomable what the Sabines got out of agreeing to the deal if it was about their enslaved people. Maybe the Romans left out the part where they legalized the unions by paying the Sabines good dowries or returned whoever didn't want to stay? In reverse it is weird that the Romans would see the need to have enslaved women whitewash their actions. They are war booty. By any Greek or Roman standards they lost their social position until they or their children regained freedom again.
To me this is the most indicative that something else was going on and the story conflates something because by straight ancient standards it makes little sense if the women were war spoils.