Yes, exactly. That's why its so stupid for them to hide my other email addresses from my friends. I listed them specifically because they are alternate means of contacting me.

My personal email addresses were exposed to my friends, but when this change occurred they were hidden on my profile and only the facebook.com address was shown.

It may not be secret, but if you choose to have the @facebook.com email address listed on your profile, it suggests that the @facebook.com email address is an appropriate email address to contact you at. I hid it from my contact information because facebook is not the best way to contact me and I don't want anyone to assume that it is because someone at facebook decided to see how many people don't do anything.