In the specific case of the question you are referring to, I agree with your sentiment. In general, I disagree with the title of this question, because legal questions regarding photography can be very important to the business of photographers.
IMO, I think the question you're referring to should be (or perhaps, should have been) migrated to Law.SE on the basis that the question has nothing to do with photography. By that, I mean that the asker is not the photographer, is not asking about their personal or business legal recourse regarding their photograph(s), etc. On that basis, if instead the asker were the person who took the puppy photos (rather than the person using them to sell the puppies), I'd have no problems with the question being at Photo.SE, because the asker would have been a photographer.
It's akin to determining legal standing: IMO, the person using the photos to sell their puppies doesn't have 'on-topic' standing at Photo.SE to ask if they can be sued for using the photos, but the photographer of the puppies does have 'on-topic' standing at Photo.SE to ask if they can sue the puppy seller for using their photos.
Note: In either case, Steven's answer basically stands. It would only have to be barely tweaked to address the other party. But the majority of it is spot-on correct for both parties.
Alternately, instead of migrating the question to Law.SE, perhaps there's an existing question here that the question could be closed as a dupe of, or be merged into.