I'm not trying to defend Facebook, but I used the 14-day deletion and it worked for me. Just saying that there must be more to this story than just "I did it and Facebook lied to me".
It also still knew a heck of a lot about me including suggestions for people I had just recently met. And some of them I only met once, in passing, never exchanged info with, and never saw again.
I did delete the account before that date with few other people (mostly because of that policy coming).
I never tried coming back but if they still kept all the data, that is pretty substantional. One could sue facebook for that or am i missimg something?
They are simply looking at the current documentation and thinking "oh yeah, I must have done that, and these guarantees were supposed to apply", when of course that isn't true if those guarantees are new, or if they never followed that procedure in the first place.