That's my point, some of us comment on the actual artwork. However- it seems that the vast majority would rather just give the "friendly pat on the back" and not even say why the image is good, mediocre, or whatever. I'm not saying that everyone will like the basics of the photo itself, but being artists- we should be able to see what is good (or not) on the image and comment on it & back it up (or what would we do to improve it). If there is nothing that can be commented about, nothing needs to be said.
Notice I don't comment on everything I look at or every image that one of my "faves" posts. However, I enjoy appreciating & viewing most of the artwork- you don't see me negatively commenting on pieces I don't like, but I will say what needs improved on such an image. Artists seeing something they like or dislike should be able to be constructive about it. Take a look at other online galleries/communities- see how it's done.
BTW- I don't need the grain of salt because I was never ever offended by any comments of my works on here. (So far) they have all either been positive or constructive.