Wanna learn something interesting about this law? No? Too bad! Once a song has reached 35 years of copyright, the creator of the song has an option to undergo "termination protocol." What this means is that the creator of the work is allowed to reclaim their rights. This is how Bob Dylan, Tom Petty, and Prince have been filling companies with the fear of God to renegotiate deals.
Now, of course, who wouldn't be enraged at the fact that their intellectual property was used to promote the cause they oppose? What makes this case special is that the writers, certainly encouraged by the artist, are pursuing legal action. Wait, legal action? Yes. Legal action.
Of course, the Prince Estate still stands by their POV that they did want the music to be brought forth, just not in the way that it was and that Tidal's argument is utter malarkey.