- purely a matter of personal taste, let'em call it “John” if they like
- purely a matter of personal taste, it's perfectly comprehensible
- a quaint historical tradition, why not preserve it
- hurts legibility (and newbies might not get it) and should be discouraged
- politically reprehensible (everyone should be free to use the word
unix) and should be discouraged
- hurts post searchability and should be discouraged
- I'm the Open Group's lawyer and you must remove and kill all usage of the word UNIX™ on this site
- look, ponies!
For me it is 3: geek folklore, just a way to refer to the many variants out there, not all of which match the patterns, but hey, they're still family.
As to searchability, this is Unix & Linux Q&A, so this word figures on every page, it should not hurt or matter one bit if a poster uses any euphemism they like.
Writing “Nix” is harmful because there is a software package called Nix which is relevant to this site. Writing “*nix” or “'nix” or the like is similarly harmful because it's confusing: are you actually talking about Nix with some weird punctuation (perhaps broken formatting), or about Unix? It's also harmful because searches will find “Nix”, not “Unix”.
Write what you mean. If you mean Unix, write “Unix”.