The brand name is the query. Somebody looking for a particular make in their own town is a customer already decided, and shops almost never publish the list of what they carry.
Restrictions create loyal customers. A coeliac diagnosis or a serious allergy turns shopping into a search for reliable stockists, and a shop that names those ranges gains somebody who returns weekly for years.
Refills are searched locally and specifically. Package-free shopping brings a distinct and committed audience, and being listed for it reaches people who will build a weekly habit around the shop.
The rules limit the content, not the ranking. Pages must not claim to treat anything, so the winning approach is stock, comparison and practical guidance, which happens to match how people search anyway.