I don't think one needs to understand consciousness to know if something is conscious or not. Much the same as how one can tell if someone is alive or dead. Sure maybe one day we can figure out a proper scientific explanation for consciousness/life but there is no reason to negate what can be perceived and immediately obvious.
EDIT: I am only making a limited point on "understanding consciousness". Not extrapolating it to AI.
EDIT: I am only making a limited point on "understanding consciousness". Not extrapolating it to AI.