They're not forcing anyone to have a public profile. You know what Facebook would have done? They would have simply made all private profiles public without any previous notification. That would have been evil. Instead, Google has chosen to follow a path where the default action doesn't compromise anyone's privacy and they have given ample time for people to decide whether they want to make their profile public or not.

From what I see, what they've done is pretty much the Right Thing To Do.