Copyright is weird and often legal ≠ moral, but I'm having a hard time constructing a mental model where it's ok to scrape a novel written by a person but it's not ok to scrape a story written by chatgpt

No it is not, data is data, whether it gets loaded from a file on disk or generated by multiplying lots of matrices.

Because the data is mine and the model is yours?

Like, in a strict literal sense, sure? Do you mean to make a claim about moral or legal differences?

Technically, sure. What is the moral distinction though?