iCloud Status "No Longer Available"... makes no sense!!!

I totally get that songs are removed from streaming services from time to time--so please don't give that as an answer--but if I have a song in my iTunes library, one that I imported directly from the CD that I own, then it makes no sense that it's not being uploaded to iCloud for me to listen to on my iPhone simply because it is no longer available.

One of the key features of Match/Music is that when it scans my iTunes library and finds a song that isn't currently on Apple Music or the store, then that song is still uploaded into the cloud for me to listen to on my devices... right? (I'm pretty sure these are the songs that have iCloud status "uploaded".)

So why, when something that was previously available is changed to "no longer available" (i.e., it is removed from Apple Music or the store), does it simply become an unplayable track from iCloud? It's downloaded on my iMac so I can play it there... however it cannot be played on my iPhone despite it showing as a part of my library???

Can anyone help explain this? Or maybe this is a glitch that Apple needs to fix? Thanks.