I believe that Stallybrass is trying to make a point about being well researched.  One must know a topic extensively before they form their own opinions.  If someone forms an opinion without looking at the research already existing in an argument, then they could be forming a biased or uneducated ascertion.  This is not to say that people can’t have their own opinions, but to have something completely original would be highly unlikely.  It’s important to keep this in mind when researching because the contributions that any one researcher may have to the ongoing discussion of the topic may be small, and they should anticipate this.  If a researcher completely disregarded someone else’s past findings on the topic, then there would be no point to that research in the first place.