I mean the free swag isn't the problem, it's the fact that these sites run off of the advertising of the games they review. It's along the lines of politicians getting all their money for the business that rely on their legislation for profits. In a lot of cases reviews are simply another outlet for advertising. Ever notice how many games get 9/10's? I really don't think as an industry we are constantly "hitting it out of the park".
Game reviews are a difficult subject. Nothing qualifies you to become a game reviewer and not all game reviewers pour hours into a game before giving their opinion. Don't even get me started on reviews segregated into categories (graphics, gameplay, story, blah blah blah 38/50). What about games that require a specific skill (difficult platforming, very in depth fighting games, etc.)?
What I find even more laughable is when my colleagues are hedging whether to buy a game or not based on reviews that they know are in fact paid for.The game has 309123 banner ads, is the background of the website, plays a trailer for the game when you load the website, do you really think their going to give it a 6/10?