I mentioned this on another thread, but I don't mind being repetitive...
When someone reviews a story and gives it a low rating because they dislike the subject matter it is a bad review. Some reviews have been negative because the story was written in a language other than English. There are also individuals who I have seen providing poor reviews to flame people. I have also seen review wars. Those are pretty obvious.
Also, technical aspects of a story are not subjective. I have seen stories get reviews of a 1 or 2 that were technically sound. Any lower than a 4 indicates substancial technical deficiencies.
All of the things I mentioned violate the guidlines given for a review. So, I disagree - it isn't subjective in many cases.