I recently read an article in a magazine which questions whether a comment made on a photograph should include supplementary questions as to why the picture was taken in the first place.
The author aknowledges that questions are sometimes asked, but theses are usually about what equipment was used and where it was taken, what post processing was used, things that have no bearing on the actual finished image.
There was, or still is, a thread here entitled 'Why do you take photographs?', but that is a catchall question, not specific to any one particular image. Do you ever look at a picture and think 'Why was that taken?, or What is the photographer trying to convey here?'
I suppose if you are moved to ask such questions you could quite rightly say, in your opinion, the picture has failed because you haven't understood or appreciated it.
Can you imagine the uproar that would occur if in the comments section you said 'What's this all about then?'
What would be your reaction?