It’s been asked before and I think it boils down to this.
The game is Unity (not Adobe Air, as previously mentioned and probably corrected by someone else). In theory that means it should have a Mac client. The purpose of Unity is to be a cross-platform game engine. Lots of games work on many platforms via Unity.
However: as a developer I can tell you the effort involved in testing increases dramatically with every platform you add. Unity is supposed to make everything the same on all platforms. Nothing ever delivers on that promise. You always end up with weird little corners of your code where you have to do something different for some of the platforms. There’s no tool to find them. You have to test thoroughly.
The game currently has to be tested on PS4, XBO, PC, iOS, and the 4,875 different extant Android configurations. This is already such a great burden, no update in the past quarter has been delivered without a need for hasty patches. We’re still encountering bugs introduced 3 updates ago. Sometimes they go away for a short time and come back. Other times we get exciting new bugs. There’s no time to test, and no time for beta testers.
So I imagine having a Mac OS client will make the game even worse, because the already threadbare QA process will be stretched even more thinly.