You can be "cross-platform" in many ways. In practice if you don't run MacOS yourself, there's just no reasonable way to support MacOS at all. It literally costs hundreds of dollars to get a compatible test environment, while most other systems (including Windows) you can download and run a in VM for free.
In practice if the MacOS support takes more than a quick headers / types update, it will likely need more care in the future as well. That means you need not just a driveby fix, but a continued commitment from someone to ensure compatibility. This is not out of hostility towards the users, but I'll keep calling things that don't work on MacOS cross-platform. (Yes, it sucks; You can vote with your money to stop that situation)
In practice if the MacOS support takes more than a quick headers / types update, it will likely need more care in the future as well. That means you need not just a driveby fix, but a continued commitment from someone to ensure compatibility. This is not out of hostility towards the users, but I'll keep calling things that don't work on MacOS cross-platform. (Yes, it sucks; You can vote with your money to stop that situation)