From the little I can find easily, she has a point. This from the Times before paywall kicks in:
Constant “unconsiderate” sex with a partner can be worse than rape by a stranger, the feminist writer Germaine Greer has suggested.
While rape by a stranger is “bloody bad luck”, it does not necessarily force a woman to reassess her whole life in the way that abuse by loved ones can, Greer said.
The Australian writer was speaking to BBC Radio 4’s Today programme as part of a round of publicity for her essay On Rape, which has prompted controversy around the world.
She said: “I think it is important we don’t diminish the effects of constant unconsiderate use of a woman's body by the man she loves..."
I agree. It makes sense psychologically - constant lower-level trauma can have a more profound effect than a big, one off event (although people seem reluctant to accept this too). It's to do with the lack of social support, the lack of escape anytime soon, the denial of your own self because you have to supress that to survive and keep going with the status quo.
I've thought about this a lot, aside from her comments. Personally, I ended up at a place where I didn't see how I could ever have sex (with a man) again as all the (consensual) sex I'd had felt... kind of abusive. Performing femininity in the extreme. It feels wrong to use the word abusive (compared to real abuse) but I don't have the words or concepts to hand to describe my experiences, compared to the useful shorthand of the word "rape". Other life experiences have shown me that it is easier to deal with stuff that can be summed up neatly and others have a concept of "that's a bad thing", compared to quietly horrible stuff that's difficult to explain so no-one understands... Consent is confusing too, if you consider all the conditioning we go through to be compliant.