That's conflating consciousness with free will. I didn't see anyone in this discussion make the claim that consciousness necessarily implies free will. These are conceptually separate phenomena. It is at that point that the claim "consciousness is an illusion" requires further explanation to avoid the trap of circular reasoning.
Sure, the view that volition is an illusion is not self-contradictory. And I get that this is a very useful view, because it lets us set aside "conscious inner experiences" and just analyze the mind as a deterministic machine with inputs and outputs. This lets us expect to eventually understand the mind/brain fully using only the physics and computing tools we already have.
Now it leaves conscious experience itself as an unexplained phenomenon, but maybe that will never become important.
The brain is always in control. When you are awake, when you are sleeping, when you are under general anesthesia, when you are sleepwalking, when you are blackout drunk, and so on.
It's a trivial statement, which doesn't say anything about why some of these states aren't like the others. And there's a strange coincidence: when the brain creates that "illusion of control", your body behaves differently than when it doesn't.