It's more that the law about "one guy decides to pirate twelve movies to watch them at home and share with his buddies" is already well-settled, but the law about "a company pirates 10,000,000 pieces to use as training data for an AI model (a practice that the law already says is legal in an academic setting, i.e. universities do this all the time and nobody bats an eye)" is more complicated and requires additional trials to resolve. And no, even though the right answer may be self-evident to you or me, it's not settled law, and if the force of law is applied poorly suddenly what the universities are doing runs afoul of it and basically nobody wants that outcome.