"Elegance resides in the vulgarity. If you are not vulgar, you will be inelegant. If you are not vulgar, you will be inelegant. In fact, vulgarity is the same thing."

That's quite right. Elegance and vulgarity are relative. Without vulgarity, there is no elegance. Without vulgarity as a foil, there is no existence of elegance;

Vulgarity and elegance will transform into each other. What is vulgar at first will become vulgar later. Transformed into elegance, such as "The Book of Songs".

Elegance and vulgarity are one, interdependent and inseparable.