Of course, it should be that the person who posted material on facebook also owns the rights to it, but it's not that simple.
And you should read the terms and conditions, see the link at the bottom of the page.
The conditions that apply at the moment gives you all the the rights to the materials you post on facebook. At the same time you give facebook free rights to use your material as long as you have an account.
When you terminate your account they will delete everything that you have write or uppload but it may still exist for an indefinite period in the form of backups.
Material that you handed out to friends will be left in the system as long as the friends doesn't remove it.
Since you almost share anything you do on facebook you can wonder if it's possbile to get rid of anything at all on facebook.. Therefore, think before you post anything. Avoid things that you think is too private. Also be careful to upload high resolution photos as it might be used by facebook for free.
They excused themselves by saying it was not their intention that the changes should be interpret that way..