4) At the heart of the issue, I think, is the 'pile on' feeling this game received. I haven't bought this game, though do want to play it... but it's been clear for the past year that this was one game plenty of people loved to hate on. All the time. Any chance they got. The leadup to Driveclub and Ryse were quite similar, but in general, it's a fairly rare phenomenon where tons of people who have never experienced the game in any significant way 'pile on', as if they want the game to fail from the outset. And it's clearly happening here too, with people trashing the game that have never played it. They defend the reviewers, despite they themselves never having played the game.
And if you're going to pull psychology into the conversation, and try to dismiss positive user reviews as 'confirmation bias', then certainly you also need to call into question many of the negative reviews as well as part of the pile on. Right? It's only fair, because it's just as true -- some people want to burn everything down, especially, for some reason, exclusive games like this or Ryse, and others are just jumping on a bandwagon and assuming it's trash for whatever reasons they do these things.
So if we're going to discount positive reviews based on 'confirmation bias', let's also throw out many of the negative reviews as well.