I think now I'd just turn it back on them and ask if they had been in the same position, would they have raped her too. Men seem to have this weird blind spot, where they don't want to be thought of as rapists, but are falling over themselves to excuse other men's rapist behaviour.
I'm swiftly coming to the conclusion that what men say about the new guidance around investigating rape allegations tells me whether or not they've ever raped someone. And yes, that might be unfair, but once they've had it explained to them, and they still believe that it makes men who are accused of rape guilty until proven innocent, then I don't think it is.