I generally agree with the premise of the article, however there are discernible differences in wine quality. What I'm referring to is the quality of the fruit and the terroir from which it comes. As an example, most CA wine is made from fruit grown in the central coast and there are plenty of good wines produced. Napa and Sonoma valleys produces much less wine by comparison, but they are generally better. Most of that is due to quality of the fruit; the soil compositions and weather patterns are conducive to growing high quality fruit. I've had a few Napa vintners tell me some years it's difficult to not produce a great wine because the fruit is so good.
Based on this I would use levels when comparing wine. Central coast wines could be grouped into a level and then Napa/Sonoma in another level. I think once in a certain quality level then the article's premise holds - ratings are going to vary from judge to judge from day to day. Comparing a Napa howell mountain cabernet to a central coast cabernet is not likely to be a fair contest, though.
I'd also add that, just as with any spirit or beer, the palate matures and there are certain aspects you favor and look for, and these aspects are typically found in higher quality products.