It's worth going to the source of the information that is cited there and reading ALL of the entries, not just the excerpts. Some have been removed since I last looked a few weeks ago, (like the one from someone who claimed that they thought the Nutro had caused cancer) but there are still plenty of positive reports. You just have to dig because they are buried, but they are there.
Don't get me wrong, there may be problems with Nutro, however, the site in question is there primarily for the purpose of generating revenue from the advertisements on the site AND furthermore is closely associated with a law firm that specializes in class action lawsuits. It was started by a journalist who used to work for AP and UPI. You all can use google as well as I can so all I can say is hunt around, and don't go for the "I saw it on the internet so it must be true" belief too quickly.