Cyrus is hardly the first teenaged minor to adopt a sexual pose, however vague, in the media, and Vanity Fair is hardly the first glossy to run topless pictures of an underaged minor — the Times' T Magazine did that in December in a move staunchly defended by the editor of the main Times Magazine.
A Disney spokeswoman called the Vanity Fair shoot "a situation was created to deliberately manipulate a 15-year-old in order to sell magazines." As opposed to, say, a situation created to deliberately manipulate a 15-year-old in order to sell a television show or the products advertised in them.
This isn't about exploitation or morality. It's about, on the one hand, a move studio looking to preserve the profits that come from selling a particular character increasingly divorced from the actress who plays her, and on the other a set of parents freaked out about anything remotely sexual and unwilling to serve as an intermediary between the media and their children.
(Images via Vanity Fair)