From what I've seen, Stewart actually reads (and considers) what people write here. Look at where the title of his movie came from for example.
If I was in his position, I would love to have a resource like this to get feedback from. There is actually some intelligent and coherent conversation going on, and the signal to noise ratio is still pretty high.
Who else are you going to listen to for some honest feedback? Music critics looking for a scoop? People on the Police payroll? Klingons (or cling-ons)?
The fact that people are Stewart and Police fans is pretty much a given if you are on this site. I don't see any bashers. Maybe a few Klingons...but no bashers.
I like to read totally positive reviews as well, but it would be kind of boring around here if everyone did nothing but heap praise on them no matter what they did. What if Stewart and Andy just accepted everything Sting ever brought to them and just told him how great he is all the time without challenging him? Hmmm....I bet it would sound something like solo Sting, and less like The Police. Sting is great, but he is even better when challenged by opposing viewpoints. This kind of "drama" is what makes life (and music) interesting.
To some people, the glass is always half empty, and others half full. On Stewart's forum, people actually get out the measuring tapes to see if it actually is "exactly" half full or empty, and if not...discuss what should be done about it to fix the problem.
While I think people can easily go over the top with this approach, I kind of like it. I don't always agree with some of the opinions people have, but I still enjoy reading them.