If FB retains complete control, you don't own your data. If you own your data, FB (or any other party) cannot retain complete control. Otherwise, what is the meaning of "own" that you have redefined the word to mean?
After the license you give FB and most other such sites, yes, while legally you own the material, practically you no longer do because they are legally allowed to do whatever they want with it. I'm not going to address the stupidity of copyright law here, however.