I think this conflates atheism with a much stronger form of causal rationalism.

Dawkins-style atheism is not “reject anything without a complete causal model.” It is a rejection of hypotheses with no explanatory gain, no empirical constraint, and unlimited ad hoc flexibility — like the Flying Spaghetti Monster.

Consciousness is different. It is first a phenomenon, not an already-settled causal model. We do not believe humans, infants, or animals are conscious because we possess a complete mechanism for subjective experience. We infer consciousness from a cluster of phenomena that need explanation.

So the lack of a full causal account warrants caution, not denial. It is reasonable to say current AI gives weak evidence for consciousness. But that is not the same as saying AI consciousness is equivalent to believing in the Flying Spaghetti Monster.