Conflating meal replacement products with junk food is silly. They accomplish entirely different goals.
That's the thing -- they're trying to convince people that their product is a "meal replacement". In the same way that caffeine and other stimulates are de-facto "sleep replacements" (and alcohol, a de-facto "self-esteem replacement") for many people. And indeed, most highly processed foods (a.k.a. "junk foods") have been successfully positioned as "replacements" for ... foods that actually come from farms, small bakeries and dairies, and so forth.
But whether any of these actually are viable "replacements" (considering long-term health and other side effects) is again very much open to question.
Right -- as with the entire junk food industry in general, basically.
As in: yes, there's certainly a big "value prop" in getting you past that next perceived craving (or legitimate nutritional need), as expediently as possible. But whether that provides a good "value" in the long run (either nutritionally or financially) is highly questionable.