See, it's funny because they're mannequins.
And the defrocked mannequin is amusingly defiant about her predicament—"Oh, what? Like you've never seen plastic before!"—unlike real human women, who get all testy when their dresses are ripped off and their naked bodies exposed to the world without their consent. Humorless bitchez.
The closer one looks, the more one sees what an amazing clusterfucktastrophe this advert really is. It hits all the high points: Objectifying the female form, playing on the concept of women's bodies as public property, treating sexual assault as a joke, making light of the reality of sexual assault (its victims are rarely so comically nonchalant; it is almost never perpetrated by women), engaging narratives about female body envy, and giving us an uproarious "disembodied things" image.
And naturally, anyone who objects is just a hysteric who can't tell the difference between real women and mannequins and certainly not someone correctly calling out Old Navy for using mannequins specifically so they can get away with serving up misogyny for laughs in a way they couldn't using flesh and blood women.
[Assvertising: Parts One, Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten, Eleven, Twelve, Thirteen, Fourteen, Fifteen, Sixteen, Seventeen, Eighteen, Nineteen, Twenty, Twenty-One, Twenty-Two, Twenty-Three, Twenty-Four, Twenty-Five, Twenty-Six, Twenty-Seven, Twenty-Eight, Twenty-Nine, Thirty, Thirty-One, Thirty-Two, Thirty-Three, Thirty-Four, Thirty-Five, Thirty-Six, Thirty-Seven, Thirty-Eight, Thirty-Nine, Forty, Forty-One, Forty-Two, Forty-Three, Forty-Four, Forty-Five.]