He's not an artists that's in some 3rd world contry or somethiing, his music exists on many U.S. services. It's probably expired cause it wasn't renewed. OR you know artists are always bitching about their pay... It could be a hundred reasons why it's not available.
You should care, because if you don't understand why something is happening, and complain about it, change will never happen. That's a fact. This is something that is not Spotify's fault, and for you to hold them accountable is not logical. Spotify has always worked hard to offer free legal music since the begining. If the music isn't available, it's because there are reasons outside of Spotify's control.