Condemning the reviewer for having an opinion contrary to your own? How scandalous!
OK, this one guy's words perfectly embody my viewpoint on this. I know that a lot, and I mean A LOT of people can't stand him, but for those that can take Total Biscuit's opinion, here's his opinion on review scores, or "Why the reviewer matters even if you don't like his opinion." [https://www.youtube.com/watch?v=HpmeOB0Zyu0]
Now, to those who DON'T like him, either because you disagree vehemently with his opinions or because you can't stand that sexy British accent, let me paraphrase him. Basically, while there are many objective things in a game you can say are broken (Framerate is awful, textures are poor, the game handles like it was coded by a two-year-old dry biscuit), there are aspects in gameplay, story, sound design, and graphical design that people enjoy differently from others, and while people try their hardest to be objective in reviews (some more than others), ultimately there will ALWAYS be a bit of bias from that reviewer.
Thus, scores should not be taken at face value, but rather should be gauged in accordance to the reviewer's preferences and whether they match up to your own. For instance, Total Biscuit flat out admits that he puts graphical and gameplay competence over story and that he dislikes puzzles in games where they can be otherwise removed without detracting from the game, and he says that people that like puzzles or deep stories should take any games that he positively reviews with a grain of salt, because the fact that HE likes them might mean that YOU don't like them.
The numbers alone are a poor judge. Reviewer's opinions are more weighted on their tastes and preferences than their numbers themselves, because their tastes and preferences WILL color their perspective on the game in some fashion, meaning that they will enjoy parts of a game that people didn't like and vice versa.
But on topic, why this matters to the topic? Well, quite simply... this guy is an idiot, and he can't see where the 4/10 reviewers are coming. Maybe they see some glaring flaws that he refuses to acknowledge, or maybe they don't like choices in the design for the game that he thinks were brilliant, or MAYBE he's just an asshat that can't take criticism.