It seems no-one's around and propping up the bar, but I'm a bottle down so I'll wade straight in.
I think what Greer was saying was that rape is unfortunately and generally a pretty fucking mundane crime, the majority of rapes are perpetrated without the use of violence (and yes, unwanted penetration with a penis is violence, but for the sake of argument she is using violence in this context to mean force).
Most rapes are committed within relationships or to people known to the perpetrator. Stranger rapes are statistically rare when looked at as a whole.
So, I think what GG is actually saying is, bring the bar for prosecution down, make it easier for women who have been raped in relationships or very undramatic ways to report and be taken seriously.
Make it so they are not dragged through the courts and treated as evidence and their lives and behaviour dissected in such damaging ways.
However, if this were to happen, sentences would have to be changed if the bar was lowered and prosecution was more likely. Her point being, rape should be prosecuted more widely, women shouldn't be stigmatized, BUT rape itself and the societal attitudes towards rapists would then be a powerful deterrent NOT to rape.
I've been raped, both by a casual acquaintance and my first husband. I didn't report it in either case because although I was absolutely raped and felt a powerful sense of injustice and fucking hatred for those men, I knew the legal process, as it stands, would not have aided 'me' to continue with my life. I would have been left stigmatised and damaged by an attempted prosecution. As it is, I have moved on without too much bother but had the legal system been different I would most certainly have reported both of those bastards.