Those establishments are not matching the meaning of abstract art, but when artist take some shot and he do not explain to customer what was it, he could create some kind of abstract from other recognizable form that could be an abstract for customer.
Macros are nice examples of those photos. First photo is with Description from artist Staged photo to abstract theme it does not say anything about the subject and form of photo it just direct customer to right choice. Second one has description Computer Enhanced Photo - Abstract View of Train rack and it tells everything about the form and subject but for customer it could be something else that only he can image. Both for me are abstracts matching this meaning.
So what about does photos that are in Abstract main category are does not been abstract at all?
Ass I was saying on my other blog in some point of view of their creators it could be an abstract, but usually it seems that on DT when we choose categories for photo for example that shows background made of green apples we choose categories Abstract-Background, Abstract-Color and we automatically add keyword background, color and abstract without consider the meaning of this words. Ok, it is machining to keyword background and color but not abstract.