I use this often for students. When you think about copyright it's an island and the island has a bunch of little bays, little cut-outs and little eddies and things in it but the island is still the nature of the rights. The island isn't a bigger island that you're cutting parts out of.
The copyright is the entirety of what is granted, including the things that have been carved out of it, these little bays and eddies. It's not an expropriation to look at an exemption. It is a part of the grand bargain between society and creators and users.