Your argument makes little sense to me I'm afraid. Of course they're past the Barbie stage and wouldn't single out the effect of barbie on their self image - it gets in there way before they even consider these things, that's the issue
But my point is it doesn't get in there. Little girls of barbie playing age are happy and confident and believe they can be whatever they want to be. The problem doesn't set in until they're much older. Now that suggests to me, at least, that the things that influence them and trigger the crisis in confidence is something else entirely.
Like I said, children do not view the world as we view the world, they do not process things as we do - and to rely on adult perspective and understanding to explain what children are thinking is a deeply flawed way of doing things.
Barbie is a piece of plastic that they bring to life, she does whatever they want her to (my sindys were the royal family of an unspecified country and had a penchant for putting on loads of layers of clothes and riding their horse on expeditions to the north pole). She exists to create fantasies. She is something they can dress up and move around and act out fantasy situations with. That's all she is to children.
It is only to us adults that she is a freakishly disproportionate monstrosity, that feeds into an idealised and over sexualised version of womanhood - if that's what you think of her. plenty of adults don't see her that way, even if they know her waist is too small. But the adult view of barbie is not the child's view of barbie!
And how anyone can be angry at an advert encouraging little girls to fantasise about public speaking and being an expert in their field is completely beyond me.