I think you're thinking to far into it. Remember that while Victoria's Secret emphasizes their models more than any other company, they do not base their campaigning strategies on said models. They chose a nice, catchy slogan and had a model (Doutzen) display the product. I am positive their marketing strategy was not based on their opinions of Doutzen's weight, that would be an incredibly juvenile thing for a company to do. Not to mention, the slogan emphasized "looking great", so they chose a model who looked great.