The study of consciousness (or sentience or whatever the appropriate term is) is definitely a valid field of research and one of science and philosophies all-time greatest mysteries. What exactly is the underlying mechanism and theory of consciousness? For example, A sound scientific theory of consciousness should be able to definitively answer the questions (and defend that answer):

  - Is an ant sentient? Why ? Why not? What is it aware of?
  - What about an amoeba? a bacteria? a virus? a cell? At what level does it stop?
  - What about the plant kingdom?
  - A rock? An atom? Why? Why not?
  - An LLM? A program? A computer?.. 
  - Will an AGI be sentient ?

The premise of the article itself is strange - maybe it was intended to stir up debate and controversy. Its one thing to say that study of consciousness lacks sound foundations. But implying the very notion that "animals are conscious" is somehow controversial? If animals aren't conscious whats the point of animal cruelty or animal welfare laws? I can take a power drill to my roomba but can i do the same to a cat or a dog? Most people would automatically say no. Its something most people intuitively understand (but maybe its learned behaviour - kids can be cruel until they learn empathy).

edit : Also the illy-dallying around the question of crustaceans seems shifty. Maybe the authors don't want to confront the moral question of boiling lobsters alive?