I think a lot of it is more subtle and more of a grey area than a lot of people are saying. I don't think its about bad guys and corruption and secret envelopes full of PS3s. That stuff is obvious and while things like that occasionally happen, it's usually called out. It's the more insidious stuff that's more interesting. I think by exaggerating all criticism to that level isn't always helpful. A lot of Shawn Elliot's posts talk about what I think is important.
Let's take a journalist who is pals with some PR people from a specific company. The PR guys are genuinely good pals with the journalist as well. They've known each other for years. They know that if they put out a bad game, the journalist has every right to call em on it and should. He may have even written a negative review of one of their games in the past. There's no bad guys at all in this equation. They're all just doing their jobs and respect each other.
But then a new game comes out, and the journalist plays it and for whatever reason doesn't like it. Part of it is broken, there's some obvious flaws, whatever. At the same time, he knows that the company that his PR friends work at isn't doing so well and layoffs are a definite possibility. He has a choice to review it, and negatively affect the Metacritic or not.
Now I don't think a lot of this has to be conscious. He isn't mapping this all out in his head. But maybe he finds he lacks motivation to really spend the time necessary to play the entire game and write the review. Motivation, now that's a tricky feeling, right? Maybe he has other obligations and things to do(there's always other things that need to be done) that he can focus on instead. Maybe he can send off a tweet or two or mention some of the flaws in a podcast, to help rationalize it. Having friends lose their jobs sucks, and it's not like that review has to be written.
Like I said, noone in that example is a bad guy. The PR guys aren't rubbing their hands together about having the journalist do exactly what they want, the journalist doesn't feel like he's purposefully not doing his job to help some company. Noone is buying anyone else's service. Its all psychological and rationalization.
Of course the end result is one less review, one less bad score, one less voice that consumers might be relying on. And maybe none of that is true, even. They weren't rationalizations, he just really was too busy.
But it is this sort of situation, or the appearance of this situation, that could be avoided by not being so friendly with PR or accepting gifts or meals or plane tickets or whatever. I think that's why some journalistic rules of ethics forbid all this stuff. Not because journalists are weak-willed and easily controlled, but because it can happen bit by bit, completely innocently. Or give off the impression of something shady. Like in Shawn Elliot's posts, a lot of stuff goes on in the mind that we aren't 100% aware of and in control of.