I am not 100% sure it would have been to determine if penetration had taken place. Don't forget that years back there was the view that if a woman did not scream or take other strong action to try and prevent a sexual assault then she could have essentially consented to sex and it would not be rape.
Given that it seems the BoE (probably on the Branch/CO recommendation) brought in some elders from outside the congregation and they were described as being old, perhaps they were still thinking about this old stance? I wonder if the question was designed to see if the girl had in some way infer consent to sex because she had not resisted enough "scripturally".
Despicable either way.