Facebook is doing more than just taking away something from their users, they’re being downright dishonest. Until recently Facebook’s pitch to users was that it was a way to connect with people that you actually know. They were deliberately closer to the closed/private end of the spectrum. And back when they had real competition (myspace), privacy was one of the key differentiators. I still think privacy is one of the big reasons that Facebook’s popularity took off like it did.
Now they’re pulling a giant bait-and-switch. Attract users with privacy, kill competition, then kill privacy to gain easy profitability. This alone is pretty disingenuous, but to make these changes behind users backs (for example, pictures that were once private became publicly viewable) shows a blatant disregard for the trust that users gave Facebook when they signed up.