I've never figured this out. It happens with almost any product. I'll see an article about a new iphone and most of the posts are from people criticizing it. If I see an article, post, forum, etc. related to a product I don't want, use, or have an interest in, I don't read it, let alone leave negative comments. What's up with these people?
I usually battle this with a special strategy of mine, which I pompously now name "valid complaint pattern".
I also use it on Amazon to see if a product is actually good or not.
The process goes like this:
1. Ignore all praise or 4-5 star reviews (those people are generally happy with their product and purchase, and rarely give good feedback on said product's flaws and faults)
2. Start reading reviews from the most negative.
3. Find out what those reviews actually complain about (sometimes it is the product, sometimes something else like shipment time or cost or whatever)
4. Find the pattern. (Are more than 50% of the negative reviews about a specific product flaw? 40%? 20%?)
If you find a pattern and a "valid" flaw, then comes step 5:
5. Does the flaw affect your usage? Will it ever?
After going through this, you can buy a product with confidence. If any flaws the product has never will affect you (well, almost never), it is a safe bet you will be happy with it.
This is also my main reason why I choose Canon. It is a bit like Volkswagen, not very sexy, but no glaring faults. A very high "lowest-level-of-play".