I get where you're coming from, but some basic assumptions simply have to be made, otherwise we could never rate ANY piece of entertainment. Everyone writing previews, reviews, etc, for them would be wasting their time, because nothing they said would have any objective merit to help anyone get any wiser as to whether that piece of entertainment is more worthy of their time than others, beyond telling them whether it falls into a genre or style they like. I'd like to think that despite people's many differences, there's certain baselines we can acknowledge as being executed well or poorly, regardless of how strongly they resonate with us on a personal level. Maybe that's just me though.
If you're saying there are commonly-understood standards in the games industry -- a shared language, so to speak -- then, yes, I agree.
That's not objectivity though; it's consensus.