Because before this, artists, especially musicians and composers, some of the most famous in history, were dying in the gutter as paupers.
Mozart.
Vivaldi.
Stephen Foster.
Schubert.
It’s not as simple as I may seem to be implying, but the short version is that copyright was a huge boon to the creative industry, or at least to the artists.
At first.
The issue is now it’s about corporations and is way out of control.
That is, between your second and third sentence is the grey area.