You're on the right side of the linguistic prescriptivism vs descriptivism debate, but I think the meaning of that word might not have settled enough yet. Personally, I think it makes sense to restrict "blockchain" to a chain (or DAG) of blocks with hashes, and refer to Bitcoin etc. technology as blockchain + POW (rather than having "blockchain" subsume the POW).

That might be a losing battle, but not sure the battle is over yet...