> The mental calisthenics required to justify this stuff must be exhausting.

It's only exhausting if you think copyright ever reasonably settled the matter of ownership of knowledge and want to morally justify an incoherent set of outcomes that they personally favor. In practice it's primarily been a tool for the powerful party in any dispute to hammer others for disrupting their business model. I think that's pretty much the only way attempting to apply ownership semantics to knowledge or information can end up.

Humans have been known to recite entire parts from plays from memory, live in front of audiences even.

This is a perfect example of 'begging the question'. Arriving at a conclusion from a fact assumed as true without evidence. Your reductio does not actually demonstrate that copyright applies to LLMs, because you did not demonstrate how transcoding is comparable to inference, just that LLMs can reproduce some passages from copyrighted works. You could also produce passages from copyrighted works by generating enough random sequences of words, but no one is arguing that is comparable to transcoding. That the people who do not share this conclusion are engaging in motivated reasoning is based only on your assumption and has no logical backing, and is therefore begging the question.