If you're referring to the fact that the Steam version doesn't have a dedicated Mac build, I've stated in a few places that I intend to upload a Mac build to Steam soon. If you're referring to the fact that the Itch Mac build doesn't run on Mac, that's because of Apples security declaring that any software that doesn't pay an annual fee is "damaged" and can't be run. You have to either run it through the Itch launcher, or use a console command to disable the security check.