That’s because just like Linux, it is Unix under the hood. :)
https://unix.stackexchange.com/questions/1489/is-mac-os-x-unix
Yep, that is the truth. Cannot argue that.
As I get older, I have zero patience for stuff that doesn’t work.
I have to pick a nit with you on that statement.
MacOS is built on a foundation of FreeBSD Unix. That's because MacOS/OS-X is based on NeXTSTEP, the Unix-based operating system Steve Jobs brought to Apple when he returned to power in the late 1990's.
So it's fair to say that MacOS is "Unix under the hood". However, all of what users interact with are layers on top of that foundation, and while they benefit from the stability and security of the FreeBSD Unix foundation, they bring their own vulnerabilities to the party.
Linux, or more properly "GNU/Linux", on the other hand, is very specifically NOT UNIX. It contains precisely ZERO UNIX code. By careful design.
The GNU operating system was developed to be a Unix "work-alike", but without using a single line of actual Unix code. The Linux kernel was developed because the GNU kernel (Hurd) never got working right. What we call "Linux" today has no Unix whatsoever in it. It more or less looks, acts, and works, like Unix, but with many significant differences.
I.e. Linux is most definitely NOT "Unix under the hood".