Sugarbrie, as a reviewer, I completely agree with you. EVERYTHING is system dependent, room dependent and dependent on the reviewer's biases, experiences, personal tastes and preferences. It is VERY difficult (if not impossible) to ever ascribe any absolute terms or adjectives to a piece of gear due to this inherent problem. What I think a reviewer CAN do is try to describe what it did in HIS/HER system and, assuming only ONE variable is changed, describe what those changes, if any, are. Then the reader can extrapolate what they need from the context. This gets a little easier if you have been follwing the reviewer for years and are familiar with his/her biases, system etc. For example, I had read Brian Damkroger's reviews for years because, for a while, he and I had MUCH of the same gear and he found it to sound like I did. Therefore, with that as a point of reference, if Brian said equipment "A" was "bright" or "hard" sounding, I could relate better from his perspective being close to mine.
Conversely, if say a Sam Tellig, who listens to some nice single ended triodes, says a piece of gear is "bright" or "hard" sounding, what I may take from that may be completely different (not because Sam is better or worse than Brian, but because their systems, experiences, and points of reference are so different).
In the end, the reviewer can only serve as a limited information source to be taken in context (not to mention they may not even be setting the gear up correctly) and as only a start to a thorough audition by you (e.g., trust your own ears in the end and do not worry if reviewer "X" likes it or not). Just my $.02.