Nah, not Weegee's picture. Actual critics.
Ran across a comment on a thing elsewhere on the internet that suggested that a critic's job is to help the artist to improve. Now, I'm not going to judge a fellow on the basis of a single comment on the internet, so nevermind who or where, we can safely assume it was a slip of the brain. Still, it's an interesting notion.
Obviously no rational thinking human thinks this has anything to do with the job of a critic. Still, it's an idea that has its roots in the culture of camera clubs, where everyone sort of had the idea that they were educators. Now, a teacher does offer a thing called "criticism" which is related to the larger thing we think of as "criticism", but which isn't quite the same thing. And that thing is certainly intended to help the student improve. Some jerkoff in a camera club, or in these modern and degenerate times, a photography forum, is not a teacher. Anything they offer to "help the student" is unlikely to do that.
Modern forum/flickr/etc "critique" is about enforcing local customs. Pictures which fail to comply with local standards are shit, and the photographer must be gently, and then savagely, urged to comply.
This doesn't have anything to do with "criticism" as it is practiced by an actual critic.
Regardless of what philosophy of criticism you hew to, the job of the critic seems universally to be to react to the art, authentically, to record that reaction, and to also write down an understanding both of the art and the critic's reaction as informed by some reasonably wide basis for understanding that the critic has, with some labor, accumulated.
React. Authentically, and in an informed way.
The object here is to provide better understanding of the Art, and its place in both history and society, to whomever chooses to read the criticism. Possibly nobody.
This might provide a buyer with a rationale for buying, or not buying. It might provide a museum or gallery-goer reason to attend or skip a show. It might simply entertain or enrich the reader. It might do nothing whatever, and go unread.
If the artist is a fool, he or she might read that criticism, and thereby learn something, I suppose. All they are likely to learn is that what they put in is not always what comes out, and if they don't know that they are doubly a fool. Regardless, educating the artist is most certainly not the point of the criticism.