Earlier quoted context omitted.
OSX is unix, in the same way that Solaris or AIX is, but I'd have split them out in a separate section for OSX specific Unix software.
Exactly - OS X is Unix(tm), but davexunit's complaint is that the term "Unix commands" implies "commands that will work on all/most UNIX/POSIX systems", not "commands for a single OS that happens also to be a UNIX".
ls /usr/bin/|sort -R|head
In my opinion it was a poorly named article with just as poor content. Many of the descriptions of the commands were not good ("lsof: godlike"). Better descriptions could generally even be found automatically: man lsof|grep NAME -A1 -m1|tail -n1