It's because in the US, you are granted the right to copy (copyright) broadly and under a number of circumstances. The creator is given a right to prevent copying under a limited (albeit very broad) set of circumstances.

Since we have a usage based assessment system on the major chip in the right to prevent copying, "fair use", which by the way is designed specifically for the common good -- enhancing the overall value to society of works that are limited by their creators -- its not about the copying. Its about the usage. Reading by an llm is fair usage in this case according to this judge's early speculations.