To be clear, it's fine that the macOS version is delayed. Sucks but I'd rather wait for a stable version and build my save game off that.
The problem is Steam not giving any indication of this before taking my 90$. Very irresponsible of them. I even read the System Requirements for macOS and there was no mention.
There MUST be a way for them to communicate this to Mac users, and if not, they need to create one. Not that I should be surprised. Steam doesn't care about Mac users and never has.