Comment by 1vuio0pswjnm7

NB. The blog refers to (a) the "Unix purist" and (b) MacOS not being Unix. Arguably, (a) is more important, irrespective of whether (b) is true (IMO it's ambiguous)

For example, the "Unix purist" might refer to someone who identifies with the "ideals" associated with that OS, e.g., relatively small, portable to potentially any hardware, free to study and modify, etc. And (b) might refer to MacOS not conforming to those "ideals" (despite having a limited license to use a "UNIX" trademark)

At this point, (b) is ambiguous; what is "Unix". It might mean different things to different people

Ironically, Apple took the "Unix" parts of MacOS from open source, non-commercial "UNIX-like" OS projects such as NetBSD and FreeBSD that are not "Certified UNIX"