When you make sweeping changes to your site and receive nothing but criticism from the majority of users (think less Terms of Service fiasco, more "we changed the layout to serve more advertisements" fiasco), it is obvious you are on the outs and hit your peak a while back. In sites that are "up-and-coming," those kind of big changes are welcomed as the, "We're getting bigger and better," scenario instead of f-ups.
I would argue that people get in a tizzy about these changes because they feel personally invested in Facebook and care about it a great deal since it's part of their daily lives. People who are apathetic to a product or service wouldn't raise such a furor.
No, I'm not a Facebook shill, but I find it enviable that they have a user base that's so clearly passionate about their service.
Ocean: A body of water occupying about two-thirds of a world made for man -- who has no gills. -- Ambrose Bierce