I'm a system administrator too (been doing it now for 20 years), and I still take care of primarily Windows PCs all day at the job. Guess what I use at home? All Macs! Why? Because for starters, I really don't want to look at the exact same OS and apps at home that I just got back from work using. I'd get burnt out on computers completely.
But additionally, when you're in OS X on a Mac, it's a band-aid fix, not a solution, to say, "Just run a Windows program from inside Parallels or VMWare Fusion, or ??" You can do that, obviously, but then you're stuck waiting for the virtual machine to start up first - just to use the program. And you're stuck maintaining the Windows image too -- complete with anti-virus software updates, Windows patches, etc. etc.
Mac users usually spent a premium price to purposely use that platform INSTEAD of Windows, so yes - they WANT native OS X applications whenever possible. You can call that arrogance if you like, but I'd call it common sense.
MRedZac wrote: Why Mac Users don´t want to use Windows ? - That´s an easy one: Because they don´t want to see, that Windows OS is much more flexible than their Mac OS, and that there´s a lot more apps for Windows than it is for anything else... My personal experience from being a system administrator for more than 10 years now: Mac Users are too proud to work on Windows in general.

