Huh, OK, I can see creepy, and, definitely can't see what the hell this cover has to do with the book, the guess that it's a depiction of Veruca Salt seems the best guess, but... Why? Really, it looks to me like some of those old timey high end dolls, that have some kind of bizzare combo creepy from a rigor mortis appearance and the Uncanny Valley.
But, Sexualized? I'm not seeing that. If a picture of a little girl in.. what is that, a feather boa or a giant mink coat? With her hair fixed neatly with a bow is a sexual image for you, I think perhaps it's not the picture that's the problem.
Bizarre Stepford wife appearance? Yup, 100% on board, the woman at the edge of the frame as well as the daughter. But that doesn't immediately equate to sexualized. Plastic, repressed even, sure. But this is not even to the level of "Houses of the Holy" album cover, which is at least arguable, let alone something like the "Virgin Killer" cover image.
Really terrible choice for a cover for this book, and easy to criticize, without needing to resort to overblown claims.