Does this fix any device synchronization problems, where someone you know had their record of your e-mail address changed to the @facebook one automatically?
It doesn't seem to be clear, as I write this, exactly what is going on there and how much is completely automatic/without consent vs. how much was "expected" behaviour. It's pretty clear that a lot of people aren't happy about it regardless, though. Even if some contact originally got onto your phone via integration with a third party service, that could have been years ago. If you weren't aware that the contact was only remaining there/unmodified because the third party chose to leave it that way, it's understandable that you might be upset if that changed without warning after a long time.
It doesn't seem to be clear, as I write this, exactly what is going on there and how much is completely automatic/without consent vs. how much was "expected" behaviour. It's pretty clear that a lot of people aren't happy about it regardless, though. Even if some contact originally got onto your phone via integration with a third party service, that could have been years ago. If you weren't aware that the contact was only remaining there/unmodified because the third party chose to leave it that way, it's understandable that you might be upset if that changed without warning after a long time.