The difference between a windows and mac version
shouldn't be so great that there should be a technical
problem. The sticks are the same...
Uhh, actually Windows and macOS are two completely different ecosystems and the differences between both operating systems (and what they do and don't support, API differences, etc.) are pretty drastic.
It's probably not financially viable to invest money and time into development for those Apple TVs/sticks/etc. as the return for the development investment would probably be too small to justify it. Also, don't believe those Apple TVs/sticks/etc. run macOS so that's also a factor.
