To borrow the religion analogy, there's the opposite fallacy of claiming the negative case "I know for a fact God isn't real", by stating you know what these kinds of information processing systems are doing fundamentally cannot yield intelligence or some kind of consciousness.
In any case, at some point one has to observe that the people who are leaning most heavily on agnosticism (the fact that we don't know what intelligence is) are the ones who say that we can't say whether those LLMs are intelligent or not because we don't know what intelligence is. In other words, agnostitism itself is used as evidence: we can't define intelligence, the thinking goes, therefore LLMs may be intelligent. There is no other evidence of any sort that LLMs may be intelligent (or any number of synonyms).
Note that this is exactly Russel's Teapot:
Russell's teapot is an analogy, formulated by the philosopher Bertrand Russell (1872–1970), to illustrate that the philosophic burden of proof lies upon a person making empirically unfalsifiable claims, rather than shifting the burden of disproof to others.
You made a claim ("a model based purely on such simple math surely can't develop sentience/consciousness") without any proof, and while doing so ridiculed people that might believe otherwise.
