My point wasn't about copying into memory being a license violation, rather the fact that you're combining two works together into a single program that violates the license of one of the works. Who is liable for the violation in that case? The user who combined the works together or the developer who created a program that instructs the user to combine those works together?
Perhaps you're selling a book that's derivative of Stephen King's novels, but instead of actually including text from his novels you insert pages that just say "insert chapter 5 from the Shawshank Redemption here". Even though it contains instructions to create a derivative work, it is not in itself a derivative work.
However if the reader follows those instructions and creates a completed work by inserting those chapters as instructed. That completed work definitely is a derivative work of Stephen King's novels.