Is the Astroturf Assumption Circular?

I'm sure my fellow wingnuts have encountered leftists who assume that anybody on the right side of the political spectrum is a corporate shill or part of an “astroturf campaign.” (This accusation has even been made when totally ridiculous.) Now that I can see a real example of an astroturf campaign I also notice that I had never heard of the organizations involved until the controversy started. Maybe the astroturf assumption is circular. First, the opponents assume that anybody on the right side of the political spectrum is a corporate shill. They then look only at campaigns run by major corporations and find lots of such corporate shills.

It looks like the corporate campaigns are in a parallel universe to the normal right-wing blogsphere. The National Anxiety Center, for example, is not on the blog roll of Instapundit, Little Green Footballs, or Samizdata. It's only noticed by other corporate shills and by leftists.