Because there's always something, isn't there? Always a reason that a woman's body isn't deemed 'suitable'. Breasts too small a la Knightley? No thanks. A middle-aged pop star? What the hell was she thinking?
Of course, Madonna is no stranger to nudity. Frankly, she's been taking her clothes off for decades. Her decision to pose for Interview is, then, perhaps less surprising than Knightley's. But it's no less powerful a statement. Here is a woman still at the top of her industry, after almost 40 years. She's weathered numerous musical trends and managed to stay relevant. Why shouldn't she pose with her breasts exposed?
After all, she pretty much started it.
Indeed, just a couple of weeks ago, Madonna posted a censored topless picture of herself from the Nineties, in response to theimages of Kim Kardashian's oiled, nude backside in Papermagazine.
'It's confusing,' she wrote. 'Nipples are considered forbidden and provocative but exposing your ass is not. #flummoxed' (sic).
Here is a clear indication that Madonna knew her latest photo shoot would shock. Let's face it, she's saying, topless pictures of famous women always have.
We might be used to seeing pictures of seeing flat chested models in fashion magazines (think Kate Moss on the beach, or backstage at a catwalk show).
But a model's body is a commodity – it's the vehicle she's using to sell products. For stars such as Madonna and Knightly, it's different. They are selling their own image, not someone elses. Choosing to bear their breasts is a feminist statement, not a requirement. They are saying: 'Here I am. Take me, or leave me'.
Of course, Madonna and Knightley both have exceptional body types compared to us mere mortals. But, the fact remains. When it all gets too 'real', we simply can't handle it.
There's undeniably an element of desire wrapped-up in all this. Knightley was criticised for being 'unfeminine'. Small boobs aren't traditionally seen as covetable. Neither are those of an older woman.
So, isn't it a blessing that we have these strong, famous women brave enough to turn unrealistic thinking on its head and show us that the female body comes in many forms?
Madonna is flying in the face of what the naked woman 'should' look like. She's controlling her own image, just as she's always done. Her attitude? Just because she's in her fifties, why should she hide away?
The sugary pink cardigan that exposes her breasts in the Interviewpicture, says it all. 'I'm not ready to button-up like a little old lady. Thanks all the same'.
We all should applaud her (preferably while wearing cut-off PVC gloves) for it.