He seems to be saying he could have pushed her off of himself and been more forceful but he chose not to or couldn't see the choice at the time. He could have prevented a rape and only endured a sexual assault, but chose not to or just felt too powerless to push a girl who maybe only weighs 120lbs away from his groin. Is it because he is a pacifist or because he "felt powerless"? I don't know. Either way. It sounds like he had an opportunity to prevent the rape but didn't because of psychology or ideology or maybe something else he is hiding. Yes, I'm reading between the lines, and maybe I'm wrong, but that's the way it sounds to me.
There are other hints in other parts of that article that nudged me in this direction too.
I really don't see a whole lot of difference between this and the position that a girl was too worried about keeping her job to fight back against her boss or is frightened about becoming a social outcast if she tries to push the quarterback off her. The fear of the consequences of fighting back against the rape causes them to choose to not take some actions which could have potentially prevented it. The notion that they should just always resist violations against their person regardless of the consequences and therefore they could have stopped the rape and are hiding something and aren't really victims is demeaning.
Now, if I'm misinterpreting you and you're not making that argument, please explain how this situation would be different than the other situations I mentioned.