Well, it isn't an anti-Windows bias... it is an anti-
Windows XP Home bias.
When the Windows NT line started there was a workstation and server version sold by Microsoft. When Windows NT 5.0 was rebranded as
Windows 2000 the workstation version was relabeled as the
Professional version (while the server version remained
server).
Through out all of that, the primary difference between the workstation/professional version and the server version was the addition of a suite of server software and additional features/abilities.
With Windows XP (Windows NT 5.1) Microsoft took the added step of disabling features to create the
Home edition of XP.
By comparison, Mac OS X is more like the workstation/professional versions of Windows NT and Mac OS X Server is like the server versions. But there isn't a version of Mac OS X (that Apple has released) that is like the Home edition of Windows XP.
Yes.
And it should be noted that many of todays server distributions (including Mac OS X Server) can be used just like any other version of the OS.
For example (people had to know
this was coming...

) I have been using Mac OS X Server 1.2 as a standard operating system on my systems for years. When Apple decided not to release a workstation version of Rhapsody and to only release it as a server OS, that didn't change anything about the base OS... it was still Rhapsody (bundled with a suite of server software).
But if you don't install (or use) that server software, the OS is just the same as a workstation version. This is just as true of Mac OS X Server 10.x.x today as it was of Mac OS X Server 1.x.x. The only reason to not use Mac OS X Server 10.x.x as a regular OS is the price (because you would be paying for software that you wouldn't be using). But in the case of Mac OS X Server 1.x.x, there wasn't a
Mac OS X 1.x.x (Rhapsody) parallel release, so to use it as a workstation OS you
had to get the server version.
I've had all the versions of Rhapsody (including all the versions of Mac OS X Server 1.x.x) for years running in my home on multiple systems. And it wasn't until about 6 months ago that I actually set up one of my systems
as a server.
And more to the subject at hand, I've had Sun systems in my home since 1999 (all running Solaris) and not a single one as ever been used as a server. In fact my total experience (to date) with Sun systems (going back to 1994) has been using them as standard workstation systems. I've never worked with (or set up) a Sun system as a server.