Not quite, Rich. It is true that Sor disliked nails, as did many others of that period, but his friend and compatriot, Aguado, certainly did use nails. Many others did too. Further back in time, the great baroque guitarist, Corbetta, had to cancel a recital at short notice, having broken a nail. The gifted lute player, Picinnini, used a thumb nail. And there is a comment from someone who saw the sublime lutenist, Francesco da Milano, perform, reporting that he used silver nails or quills on his fingers - fingerpicks!
The truth is that both techniques have coexisted for centuries, and will most certainly do so for as long as people play guitar-like instruments. I celebrate that. I'm not saying to anyone that flesh is better, though I very often am subjected to the opposite from those who claim the nail technique is the "correct" way to play.
There are two types of flesh players: those who choose to do so, and those who have it thrust upon them, due to not being able to grow or use false nails. In neither case are they doing it wrong.
Let's allow more variety in our little world...