I think you kinda miss the point here, fluffwise...
The fact is: they don't put on the pasties, and nobody else put them on... just like nobody did their hair or put them a necklace.
They manifest themselves in that form, maybe because they are shaped from strange nightmares or their corrupted memories of their ancient past, who knows...
A lot of creatures from folklore (expecially asian folklore) shows some kind of weird connection with human fashion or habits. In the majority of the cases is safe to assume that they don't invest a lot of time everyday dressing and tailoring their apparence. They simply manifests thenselves with that shape, consciously or not.
Also, a lot of fictional creatures from artistic media share that same characteristic today: take a look at Valfor or Ixion from Final Fantasy X, for example. they are spirit beasts, and they are covered vith rings, necklaces and so on. obviously they don't dress themselves, and clearly nobody put all that jewelry on them. THey are manifested like that.