Or could it be that the people complaining about Unity doesn't know how to change to to Xubuntu, Kubuntu and so on? A lot of the comments are "Unity is crap" bla bla. I just don't get it, If you don't like Unity, just use Xubuntu or whatever.
The complaints are usually being made by people who don't have anywhere to go. For someone who has used and has learned to love the Gnome 2.xx desktop moving to XFCE or KDE is simply not an option, and Gnome 3.0 is not a way forward. Where do those people go?
This is why you see so much hate for Unity. Not just because it represents a decision by Canonical to double down on pushing their renamed "Netbook Remix" on people under the guise of offering an alternative desktop to Gnome 3, but because these people feel they have no place to go.
MATE may be an answer some day, as long as its project continues to be worked on but for now all that exists is a few distros still shipping with Gnome 2.xx and of those most of them are rapidly approaching an end to their supported by dates and no longer seeing any application updates.
For all that it is a feature of Linux distros to have all their applications available from one repository, it is also a huge flaw because it requires that the user always upgrade if they wish to continue using applications. That is why there are so many people angry. They have less choice now than they've ever had with their computers and seemingly no where left to go with a future.