If they aren't completely objective, I'm still pretty sure it would be reasonably hard to find someone who would ask for a game to be emotionally bland, or to have gameplay mechanics that are dissonant with the story. If someone was trying to make a game, it's a fair rule of thumb that those are things to avoid and I doubt many people would criticise a review for calling a game bad on those counts.
If anything, I thought bugs were the more subjective one, because you can get a lot of enjoyment out of a buggy game, and Yahtzee explicitly listed it as one of the things that made Skyrim fun. There are less people who've described a game as great because it had a boss fight where you beat the boss and then he beat you in a cutscene (although I feel like a lot of my points could probably be tidily summed up under gameplay/narrative dissonance).
I figure they have about the same level of objectivity as using a dutch angle to create an unsettling emotion in a film. A film that matches dutch angles to unsettling is going to be doing the right thing 9 times out of 10, if a director didn't know what one was meant to do and used it in the wrong place, it probably would confuse the audience and detract from the emotion of the film and be a sign that he wasn't yet an experienced director with that showing in the project. But there are exceptions to the rule and it isn't going to go over the same with absolutely everyone