Agree it has nothing to do with AI. Even if we, for the sake of argument, agree that human beings are machines, why should the appearance of human-mimicking reasoning imply sentience above and beyond any other (complex?) computation? Why are LLMs possibly sentient and not, say, pocket calculators?
Actually, it has nothing to do with AI. It's a statement by the author that they believe the consciousness is a product of the brain and nothing more. That view reduces humans to machines, the only difference being in the material.