They are not carnivorous because they are not using the dust as a source of nutrition/energy. Besides, an animal that eats dead skin (like dust mite perhaps?) would rather be classified as a debrivore, and most meat-eating animals (or at least the ones that eat mammals), from wolves to pigs to crows to various invertebrate debrivorea, would happily eat a dead human or at least a part of them if provided with one, but are yet to start actively hunting us, save for some very rare exceptions.
They are not carnivorous because they are not using the dust as a source of nutrition/energy. Besides, an animal that eats dead skin (like dust mite perhaps?) would rather be classified as a debrivore, and most meat-eating animals (or at least the ones that eat mammals), from wolves to pigs to crows to various invertebrate debrivorea, would happily eat a dead human or at least a part of them if provided with one, but are yet to start actively hunting us, save for some very rare exceptions.