The quote, "Sociology is not just a matter of opinion," in my point of view, simply means that one cannot rely on his or her own opinion, now just the opinion or another. I think the purpose of this quote was to put to use our research on the methodologies of sociology. Somethings I found on methodologies include scientific methods, the characterization of the subject(s), a hypothesis development, prediction, experiment, evaluation, correlation and causation, quantitative and qualitative, objective vs. critical, and ethics. Sociology is much more than the point of view one might have on a given subject.