I kind of think it's cute. I think it's being tongue in cheek about the saying, "You can never be too thin." I don't think they want people to be annorexic. I think that, at worst, they might be saying that these pretzels might be a healthy snack alternative (though the article points out that given the calorie content, they aren't). But I think we have far more disturbing advertising images to get our panties in a wad over. Really, I do.
And when you have other articles, like this one about a British Health Minister that says calling kids fat will shame them into losing weight, then I think we have bigger issues to tackle than a pretzel ad that people believe is promoting annorexia.