But I don't remember apple removing many features from the finder or changing the menu bar since OSX was launched, so I think your simile is misaimed.
No vague assertions, please be more specific
"yet their fan base not only approves of it, but they somehow justify"
Coincidentally their "fan base" is composed of several people with design and user experience knowledge (in various degrees) so I believe their acceptance of things has a basis. (And it doesn't mean they accept everything)
Edit: as an example quoted by the other commenter, inversion of scrolling direction was a big change. But it is configurable, so you can always go back
The natural scrolling makes sense if you're using a trackpad, but for a scroll wheel it's awful
Yes, the 3-finger swipe can be only done if you have an Apple trackpad, either the built-in one or you the separate one (I have one of these and it's nice, having come from a trackball)
Not sure if you can do this with the magic mouse (maybe there's a different way)
I don't think this is true. They get crucified because they're trying to create a desktop experience for a market that doesn't exist.
Their GNOME 2 user base were all workstation users who were using GNOME 2 in their day to day lives get get work done. Instead of making GNOME 2 better (under the hood) the GNOME developers decided to jump onto the tablet UI bandwagon and drastically change the UI. However, their user base simply didn't need this, they just wanted a more stable desktop top rather than a different one.
In my opinion, the crucial mistake the GNOME developers made was forcing this new UI experience through peoples throats by chucking out everything they accomplished with GNOME 2. GNOME 3 should have been a separate project under a different name. If it really was that much better than GNOME 2 then at least people had a choice to switch. But now we can't and everyone is scrambling to find a GNOME 2 replacement..