Hm. Not to mention, it is not like the people who post on that site only use that site exclusively. Many people have 2 or more sites they frequent, according to what they use them for.
Look at this very Wiki and forums for example: many people here like anime, but it'd look awful if people just started discussing the latest anime season in the front page alongside the reviews. Likewise, I don't use neither TVTropes nor BWW to post my drawings unless it pertains to a specific topic, I go to sites dedicated to to art, like deviantART or SoFurry.
So yeah, what M said, it is not a critique site. It's a fandom site. Expecting well-thought, professional-like criticism from it would be like expecting pears from an apple tree.