Honestly, I wonder if this doesn't have to do with the privacy settings being removed... I had the same issue as the people here.
For the past week, everytime I was browsing the site on a PC, I had refused to select the acknoledgement of the privacy changes. I loved my profile being private and unsearchable
The update (not a brand new install) of FB kept on crashing on my Iphone 5 over the weekend.
Until... I went on a PC and clicked on the"I undertsand" pop up that didn't want to go way this time and was making the browsing of the website impossible.
Guess what... my profile, that used to be private, turned into public and the Iphone update worked fine this time. Suckers!
So, I can now update and use FB on my Iphone.
As my profile is now fully public, I have no choice but to delete the app and close my account.
For those of you who did not accept the privacy change, it was probably done in your back by batch over the weekend, which could explain why even if you didn't agree to anything, as you were forced to, then it is now working.
Long story short, even though my theory is probably not the thruth, I am leaving facebook!
Ciao,
A ex-facebook user