Facebook makes A LOT of changes. Most of them I really have not liked (at all), but I tolerate them because I am receiving a FREE service from them and figure that I don't deserve much say in the matter. But, when they change my profile information without my knowledge, that really bothers me.
I have no idea when they changed things, but I just noticed today that my default profile email address was one of Facebook's choosing (email@example.com) and my other email was set to "hidden".
If you want to change your email address back, this is what you need to do:
On your timeline, click "About" on the left-hand side.
Scroll down to "Contact" info and click on "Edit".
Click on the circle (on the right-hand side) to hide your facebook.com address from your timeline and then click on the circle to the right of your chosen default email address so that it is changed to "shown on timeline".
Make sure to scroll down and "Save" your changes!
I can't help but wonder what they will change next......