This article seems to conflate not liking a game with thinking it is a bad game. Your focus is upon prejudging a game so as to avoid wasting money. While this is necessary to be anything approaching a reasonable consumer of any medium, letting dislike get to the point of believing that the author is a hack, that other people shouldn't like the work, or that the work is outright morally objectionable requires a great deal more experience than those provided by previews, reviews, and the like. Farmville's kind of a bad example, as reading about Zynga's dubiously legal shenanigans to gain profit allow people to raise reasonable moral objection, no experience with the game necessary. So, I'll use your Twilight example instead: It is reasonable to have heard about the book and decide that you won't like it before even reading it. It is not reasonable to decry its treatment of vampires, women, or its audience's IQ before having read at least a few chapters of Meyer's actual WORDS. Otherwise, you can only know secondhand what such treatment actually entails. This is a problem because the details are easily skewed by those who already have a strong opinion about the book (in either direction). If you do have such objections to a work, it is fine to discuss it in a mature manner with those who disagree with you, but if you don't actually know what you're talking about, on what grounds do your opinions stand?
EDIT: For the record, I also disagree with those who say that Yahtzee was "biased" when he reviewed SSBB, or at least that his opinions were invalid on those grounds. I greatly enjoy Brawl, but the game flat-out REQUIRES a great deal of experience with Nintendo games (that is, a pro-Nintendo bias) to derive half of its enjoyment. The concept is even marketed as a form of wish-fulfillment; a resolution to the typical nerd fantasy of "who would win in a fight" that is only of relevance to Nintendo fans. Thus, non-Nintendo fans should not be expected to enjoy the game, and for them, Yahtzee's opinion is perhaps the best gauge of whether or not they would like the game. This contributes to a large portion of Yahtzee's criticism of the game ("Who the hell is Marth, and why is getting him considered a reward?"), and the rest of it, if memory serves me, were more minor points. The only thing Yahtzee criticizes that I take issue with is the allegedly too-far-zoomed-out camera... but who knows? Maybe us SSB fans have an easier time because our eyes have been trained by the frantic pace of the previous games. The camera IS farther away than in the original and Melee, and some specific character situations can produce particularly hard-to-see results (try playing a green Mr. Game and Watch on Smashville at night, or telling the difference between a blue and black Marth)