It's about the cost of credit. References are free in academia. In music crediting means paying royalties. In academia the assumption is that citing is fair use

It's about the cost of credit. References are free in academia. In music crediting means paying royalties. In academia the assumption is that citing is fair use up to a point (a paragraph? a page?). Since songs are much shorter, the window for "fair use" is also much shorter (5 seconds? 10 seconds?).