It should be noted that Linux generally does actually conform to UNIX standards, though, and that two actual Linux distributions (Inspur K-UX and EulerOS) have in the past obtained UNIX certification. While this doesn't make all Linux distributions UNIX certified, it puts a rather large dent in the claim that they cannot be qualified as UNIX because of some claimed divergence from the standards.
(It also seems odd from my perspective to call exactly only those two Linux distributions "UNIX" unless you're essentially using it as a legal qualification and not a practical one)
> While this doesn't make all Linux distributions UNIX certified, it puts a rather large dent in the claim that they cannot be qualified as UNIX because of some claimed divergence from the standards.
No one is claiming it can't be a Unix. But as you noted, Linux distributions normally do not meet the legal criteria, nor are they descended from one that did.
Legally Unix is a trademark and has a very specific legal meaning. If you don't mean that legal meaning, then it is clearer if you use another term. The usual term is "Unux-like"; that is the widely-used term and it has been for decades.
A rose by any other name may smell as sweet, but calling it a different word risks confusion.
(It also seems odd from my perspective to call exactly only those two Linux distributions "UNIX" unless you're essentially using it as a legal qualification and not a practical one)