Apple increasingly makes decisions that seem at least strange and sometime almost unfathomable to even dedicated users of its platform.
For myself, whilst I can appreciate and support any move to produce a more appropriate application for a specific role, I share the view of others that it ought to be available for Mac OS, too.
As an aside and perhaps an unfair or ignorant one, I admit, I would rather they had spent 18 months on improving Apple Music, which provides me with continual frustration, something that I don't recall happening with its predecessor iTunes.