I’m assuming people who already bought the game can still play it?

Haha, online games licensing sucks. It’s almost as if, when we discovered we could distribute media freely and infinitely by digital means, we should have restructured how media and licensing works for these products. but we didn’t, and now we have bizarre situations where publishers try to delete their own games from existence rather than spend some upkeep for music licensing

It’s still available on GoG.

https://www.gog.com/en/game/spec_ops_the_line