Criticism can serve a number of purposes. I think in the context of critiques of photographs by other photographers, the main purpose should be to help the photographer sharpen his or her vision.

If the photograph doesn't affect the critic in the way the photographer intended, that is useful information that can come out in critique. Also, sometimes someone else might see a possibility in an image that the original photographer didn't consider, so the printing or rephotography process in the critique circle can become a kind of conversation where different versions are tried, perhaps leading to a "final" statement of the photographer's vision in response to this kind of dialogue, or perhaps many interesting variations.