It has more to do with publications writing unsupported reviews for products trying to get clicks. This is no different than tabloids printing sensationalized headlines to get eyes when you're standing in line at the grocery store.
I just ran a search for 'Nintendo Wii U' and the whole front page contains none of these types of articles reviewing the Wii U. The front page has articles from ABC News, e3, Youtube, Amazon, etc. If someone is searching for 'Nintendo Wii U Reviews' and the results return the only page's available that display themselves as 'reviews' then who's fault is that? The searcher, who is uninformed enough to not realize that the Wii U can't be reviewed yet because it is not available, or Google, who assumes the searcher wants to find reviews for the Wii U, regardless of their validity?
If I search for 'aliens are real' I get results that support my search query which assumes aliens are real. It's not Google's job to decide if 'aliens are real' or not. It's job is to return relevant results for what I searched for. If I want 'Wii U Reviews' then I'll get reviews, regardless if they are valid or not.