Hey not sure if you meant to answer to my post or to the question itself. But, yes I agree with you. It does depend on how the author defines "decadence" but as a concept I think it boils down to questions about morality and freewill.
I think there were some authors/artist back in the day that associated with the decadent movement because they ascribed to a new aesthetic that the mainstream "good society" was not promoting. There was experimentation in art forms that display sexuality, grotesques figures, morbid things (think Edgar Allan Poe) and it was looked down upon. For me personally, I think discord creates more creativity and is definitely influential. So yes, I think there is a fine line, especially, in how we judge what is and what is not decadence. To each their own?