A photographer's responsibility

I just saw an image that raises this interesting debate. It is a picture of an orangutan in a zoo, and the image is shot to emphasize the creature's 'sadness'. The image is Photo of the Day over at Photo Radar and you can see it by clicking here.
The image description states how the photographer visited the zoo and was aware of how sad the animals looked. Now 'looked' is the key word here. This was my response -

'This shot emphasises sadness, but is the subject actually sad? Photography is a powerful tool but do photographers always choose to portray the true message? This image is clearly a case of anthropomorphism. We assume the orangutan is sad because of its slumped stance, its downturned mouth, and the lack of 'nature' in it's enclosure. However, a downturned mouth in primates does not indicate sadness, it indicates relaxed facial muscles, which in turn indicates a happy, content primate. An agitated primate would be active, baring teeth. The slumped stance shows the same, relaxed muscles, showing a relaxed primate, rather than an active, agitated one. We assume that because the orangutan isn't in lush vegetation it must be somehow worse off than its wild counterparts, do you really think that the orangutan cares if he/she is swinging from real vines, or ropes and straps? Zoos work very hard to recreate an environment in which an animal can act as it would in the wild, which is why they come up with complex enrichment items, allowing animals to search and forage for there food, puzzles to keep them occupied and mentally stimulated, as well as a host of other things.
The problem with humans is that most of us see ourselves reflected in these animals, especially primates who are so similiar to us. Because of this we anthropomorphise and make assumptions about an animal's welfare/state of mind based on an equivalent human expression without fully understanding the animal itself. As I said before, this is a great photo, but it really calls into debate the issue about a photographers duty to represent the truth, rather than an askewed view of it, altered and affected by human perception. This image will no doubt be debated till the cows come home.'

I would love to hear everybody's thoughts on this. It could very well be an interesting debate.