They say a reviewer is supposed to answer three questions:
1. What is the work trying to accomplish?
2. Does the work accomplish that?
3. Why or why not?
A.O. Scott, movie critic for The New York Times (who, in fact, wrote a great article on the nature of criticism not so long ago). Sure he can be snarky, somewhat from irritation and somewhat for the purposes of entertainment (he wrote the funniest movie review I've ever read, and snark played a huge part in that), but he's always getting at something deeper.
I'm a reviewer myself (not of Mr. Scott's caliber, but I'm trying); I reviewed movies once upon a time and now I review books and graphic novels for Booklist . The reason all this is banging around in my head now is that the trade reviews of my own book are starting to come in. I'm finding it rather agonizing (like every other artist who ever lived, I'm sure) -- even reading the good reviews can be a gut-twisting experience. Certainly, I'm lucky to be in a position where my work even gets reviewed, but it sure struck my reviewer self in a disturbing way: shouldn't reviewers remember there are real people who produced this work and that every comment carries huge weight? Shouldn't reviewers remember that they are potentially making or breaking careers?
The final lesson my reviewer self took from all this is that no, of course reviewers shouldn't be considering that, at least not in their critique of the work. The reviewer's final responsibility is to their readership, that needs clear, honest appraisal of the art in question to help guide their purchasing or even expand their understanding of the work in particular and the form itself. As torturous as this process is proving to the writer me, I hope in the end, it makes me a better reviewer. It's still a long way to Mr. Scott's level, but maybe this is a step in the right direction.