I've had some odd comments as well. I do find most comments fairly helpful but for Out of Place (mine was of a concrete spiral staircase stood on it's own in the middle of a field. The comment was that "it didn't fit the challenge" Obviously there is someplace that is full of stairs in fields............:)
For Wheels I've had a comment that the commenter said he/she wouldn't have known was a wheel if the title didn't say it............in all honesty there is no way you could look at the photo and not be able to say exactly what it is. However...........
I got this comment from a newbie...
"ok... so we have wheels in this shot... but no story behind them... the title does not help either, so all we have left is the sharpness of the picture..."
Interesting, no? you all got stories behind your pics, right? Now how do I improve my picture with this new insight?
interestingly enough, one of the comments i got said that "It feels more like a story, now, which distracts from the impact of some really interesting subject matter." - different people will like and dislike the same aspects of your submission, that's to be expected... still, i consider this comment helpful...
I used to feel bad for leaving constructive comments-I thought it would be interpreted as negativity. But, I always include the particular dislike and ways to improve it i.e.-lighting,blur,grain,comp.
After I noticed people checking the "helpful comment" box, I got excited that my critiques were actually worth something. To sum it up, I think commentors should try and elaborate on dislikes and ways to improve the photo's score...it seems like many of us rely on comments to help improve our work.