It's not that unix folks don't appreciate it, but that it's not clear what to appreciate. From solely a personal standpoint, years of both using and programming on Windows taught me nothing about its values. However, I can talk about Apple and its values for hours and I've never owned anything Apple except its keyboard.

Joel, the author of the article you linked to, states the core value of Windows as being "useful to non-programmers" basing it on "By contrast, Windows was created with one goal only: to sell as many copies as conceivable at a profit". The former does not follow from the latter.

Microsoft didn't need to rely on usefulness to anyone to sell many copies, and they didn't. As for why Linux isn't non-programmer friendly, I beg to differ. Android is a prime example and the argument as to why it's not doing well on desktop, as Linus Torvalds puts it, is because no one ships Linux on their desktops. Microsoft has a lot to do with that. When and if they ever do, Aunt Marge will be as happy using Linux without even knowing it's Linux (does the average non-programmer know that Android is Linux?)