Because they are insulted by Windows users as “falling for the hype”, “paying for the design”, etc. (yes Michael, I’m looking at you too).
Sorry guys, but you are wrong.
First of: Like me most Apple users know both MacOS and Windows, often intimately, and make an informed choice. Most often the same cannot be said for Windows users who’s experience with Macs is often zero or restricted to a very old Mac still running somewhere (while equally old Windows boxes have died a long time ago)
I accompanied about 40-50 people in their switch from Windows to Mac, and the more experience they had with Windows the longer it took them. The biggest problem was always to get that complicated way of thinking that Windows seems to install in its users out of their heads.
Secondly: Design is MUCH more than looks. It’s like those doofuses saying that Evolution is just chance when Evolution is the very opposite of chance - they have no clue what they are talking about.
THAT’s what design is all about. Anyone saying silly things like “just paying for design” shows himself to be completely ignorant. Pretty much in the same class as “Xojo is just a toy language because it is Basic with Goto and such stuff”.
Thirdly: Mac users are described as “fanboys” but talk to a Windows user and Windows is the best thing since sliced bread - until a new version comes along. Then all of a sudden they talk about how bad the old version was and what utter crap. Happened with (yes, I was there) Windows 1, Windows 2, Windows 3, Windows 95, Windows 98, Windows Me but not WinXP. Because VISTA was such a disaster that I recommended to everyone to NOT install it (but did they listen?). VISTA was such a disaster that Microsoft renamed ServicePack 1 to Windows 7 (internally Windows 6.1) to escape the bad reputation of VISTA and charged full price for it. Win 7 is rather nice (but still weird in that Microsoftian way). And Win8 is a disaster again (though not on the scale of VISTA).
Fourthly: I’m sick of paying the Microsoft tax. I am considered the “computer expert” in my expanded family / circle of friends. Most of them started out with Windows, and as long as a Windows PC works it is ok. And if things go wrong and you know what to do and you like to tinker that’s fine by me. But most users don’t. And it is me paying with my time for all those cheap bastards trying to save a few bucks. Supporting 40-50 people is a full-time job with Windows PCs. About 3 years ago I refused to do any more Windows maintenance. I told them “Get a Mac and I will still help you - I even help you buy one second-hand, set it up, train you.” It takes about 4-8 weeks in which people complain and wonder if they should not have stayed with Windows but afterwards every single one (except a gaming enthusiast whom I recommended against switching) said “Windows? Never again”. And funnily the most ardent ex-Windows supporters are the most rabid. Will they never learn?