I don't think it's irrelevant (or non-NPOV) to identify the political affiliations of the critic-sites. "Progressives" tend to oppose libertarians like Stossel in principle, and their criticism reflects this. The http://www.crooksandliars.com/2006/06/18.html#a8765 link is a fairly savage attack that calls Stossel a pathological liar. That's not a balanced criticism.