Taken from an article from Remy Charest:
For a variety of reasons or choices, making wine exclusively from grape juice, without any additives at all, may not be possible or desirable for some vignerons or winemakers. Certain grapes may be less suitable for the sulfur-free approach, for instance, because they are more sensitive to oxydation: grenache often seems to sink fast in no-sulfur versions, and whether or not it’s because of oxydation, I’ve never had a cabernet sauvignon “nature” that I found halfway pleasant.
Let’s face it: back labels and technical sheets are generally a collection of clichés and good intentions. “We made this wine from quality grapes, picked at perfect ripeness from the carefully-tended Le Best vineyard, and gently treated in the cellar to express varietal character and the unique qualities of the terroir.” There, I’ve just written 90% of the back labels in this world. Total marketing BS.