There are a huge number of reasons why this may be the case.
This is, AFAICT, a personal blog and so I, personally, don't believe that the author owes you -- or anyone else -- any explanation whatsoever for what topics they choose to write about and/or what tools they choose to either "promote" or "ignore".
Why do you feel otherwise?
He seems to show up with disparaging remarks whenever there is thread linking to that domain
Whether the author owes me anything or not is irrelevant: I‘d still like to know why he keeps on doing that.
I tried running it (for mostly ideological reasons) on a couple of Macs I had lying around. Not only was it impossible to run on the Macs due to lack of EFI in SmartOS it was also problematic on other machines I had once I got it to even install.
(they have their own answer to libvirt)
If I were to run a hypervisor today Id run coreOS or fedora. But there are no bad options if it fits your usecase.
The document even tells you that this is not an installer:
“This is not an installer and does not install the live image. The script is simply for data setup. You will still need to boot from live media.”
Whoever can read is at a distinct advantage.