The tu quoque argument doesn't really work here. LLMs are specifically designed to output either material from their training set or instances that look statistically like it. Humans are not.
But our material natures are such that we have a profound need for external training sets - we don’t develop linguistic abilities unless we are exposed to a lot of speech. We can’t hear or produce phonemes in general that we are not exposed to during the training years.
Literacy, libraries and printing are so powerful because they extend the lifetime and size of our training material; if we each had to invent culture from our individual powers and skills, we would be living worse than anyone for fifty thousand years has lived.
I would argue that we are not - because we do not have a rigid partition between training/test. Our ability to reason speculatively rests to some extent on ability to produce outputs that we have not seen before and which are statistically not like that which we have already seen. How we know which of these outputs to keep, and which to discard is (afaik) an open question.