In my personal opinion, I argue that the effort to make before-private settings now-public with user confirmation is the "unethical" part, not necessarily the implementation. I will cede a point here: calling it unethical may be a little bit too strong. But I definitely do not agree with the decision, for the following reason:

Knowing that a design change will cause a certain percentage of the user base to expose their personal information (which retroactively they did not wish to make public) while providing little added benefit to the end user is what bothers me.

Facebook is known for its perseverance in the face of user complaints, which I can respect. I thoroughly agree that at times user complaints and petitions (such as those against the various site redesigns) are unfounded, as there is a clear greater good. I do not see the greater good of the new public-pages push, and thus, do not respect the effort to push user information into a more public space.

If you could point out benefits users receive by making more of their information public, perhaps I could be convinced.

[edited for spelling]