"I get what they mean, but macOS is even Unix certified."

What do they mean?

To me the blog author is primarily focused on the issue of _control_, i.e., being able to control the hardware that he purchased as opposed to letting a company control it, e.g., through pre-installed software, remotely installed "updates", default settings, etc.

He cannot control its default behaviour hence he wants to "slim MacOS down"

"UNIX" was a pun on the name of another OS that allegedly was accused of being too large and complex. That OS, Multics, was designed to run only on specific hardware from GE and later Honeywell

UNIX was a smaller, less complex alternative that, after its rewrite in C, could more easily run on a variety of hardware and be modified by the people using it

Apple does not allow people using MacOS to modify it

MacOS is proprietary; unlike AT&T's UNIX it has not been released into the research community resulting in non-commercial, open source "MacOS-like" OS projects (HackIntosh notwithstanding)

A user cannot write programs for MacOS without restriction by the company, e.g., prior approval, "developer" fees, etc.

MacOS cannot easily be used on a variety of hardware, only on Apple's proprietary hardware

Compared to non-commercial UNIX-like OS, MacOS is larger and more complex

https://eclecticlight.co/2023/12/04/macos-sonoma-is-setting-...

The next sentence is also interesting actually.

> It’s a closed-source proprietary operating system

Most UNIX systems were proprietary & closed source though?

> macOS isn’t, and never has been, Unix.

MacOS is the most UNIXy of the UNIXes

1. Comparatively heavyweight

2. Proprietary

3. UNIX APIs

Yes on paper. Submitted version differs from what customers run at home/work.