He can't test it because he doesn't have a Mac or Linux. Give the man 5 fucking minutes before you start complaining about a FREE game that he made for US.
i understand how he cant test the mac version (kinda) but then again he can make a mac vm (then again i heard they arent easy to make) to test it on mac and use something like wsl to run the linux version still dont think everyone should complain like children tho