I think part of the aversion is that we're seeing a generation come into being that doesn't understand that Unix > Linux.
The way that for Windows people Unix was "other" and bad and scary. Now we have legions of programmers who were brought up on Linux, and now think of Unix as "other."
Having had the fun experience of compiling a fairly heavy UI application on Unix, they all seem pretty "other" to me. Solaris didn't do anything weird, so it was maybe the only non-other. HP-UX had something really weird with linking and I feel like it was lacking some shell commands that were fairly standard. AIX did something strange with shared libraries and their error messages were decidedly non-standard, although they all had unique code at the beginning so at least it was easy to search for problems. I think AIX was the only one for which malloc(0) = 0, all the others at least produced a valid pointer. I can't remember what the problems with Irix were, I think it was just that by 2008 Irix was just old so getting an up to date compiler was troublesome. Linux was just as "other" compared to the rest, but it was increasingly full-featured. Solaris kept up for a while.
And admining them was definitely very different aside from the basic shell commands.
The way that for Windows people Unix was "other" and bad and scary. Now we have legions of programmers who were brought up on Linux, and now think of Unix as "other."