In this case, it might make the overall thrust of the article - that G+ is reducing the quality of Google search results - worthless, because it calls into ques

In this case, it might make the overall thrust of the article - that G+ is reducing the quality of Google search results - worthless, because it calls into question his credibility with regards to his ability to assess that quality. It's like Yelp reviews of sushi restaurants that start with "I don't usually eat sushi, but..." ... the points involved may still be valid, but the overal credibility of the assessment is seriously impaired.