Isn't the problem here how we are defining 'ordinary'? To me, an 'ordinary' person is one who doesn't stand out in teh crowd, who holds views and does things others would consider unsurprising. It doesn't mean 'right' or 'ideal'.
IMO rapists in our society are ordinary men. Not all rapists are ordinary, though - and those who are not, those who are caught and studied by psychologists and get into the papers, are often quite obviously not ordinary men. But the majority of rapists must be ordinary, or we would notice them, because they would stand out in the crowd.
Does that make sense?
I don't see why it's upsetting (though I see it is for some) to say that rapists are ordinary men. I don't have a problem with accepting my DH is unusual in that he doesn't consider it's ok to initiate sex when I don't want it, or to carry on when I'm not interested. I think it's really sad that this makes him unusual, but looking over this thread it is quite obvious that it does.
It's like the 'ordinary men watch porn' argument in reverse, IMO: people who want to defend porn will insist that all 'ordinary' men watch it, and that any men who say they don't are lying. Of course we all know men who don't watch porn, but society wants to normalize it so society does. Likewise with rape, society wants to pretend it's not ordinary men, so we all want to resist the idea it is.