There is a hypocrisy in such arguments. People damn the weighing of content when it is detrimental to a game, but will also praise the practice when it gives a game a serious boost. There are a multitude of games which have scores that are almost fifty percent plus a result of the content.
Want an example look at Mass Effect. A game which has a whole host of issues. The game play mechanics are really weak, it suffers from bugs, crashes, and lag. On the visual side the game is poor, the environments are generic, and the layout was fairly heinous. Which makes Mass Effect a below average shooter. A game that mechanically speaking should be scored at around fifty or sixty, but it is the content that drives the game up to a average score of over ninety.
This is where this bashing of 1up is hypocritical. You cannot accept a thirty to forty point upswing for a game based on the content, without accepting that the opposite cannot be valid as well. The content is a constituent of modern reviews. The gamers expect this, and they apply the same logic themselves. When judging the value of a game. So if good content can make a game awesome then it is only logical that supremely bad content can see a game being marked down to total crap.
You should read what Joel wrote. Saves me the trouble of writing my own opinion as his statements reflect my opinion on this matter..
In basic, there is proffesionally reviewing, and then theres a 'immature person with a free game who decided he was gon' write about it !'