Right, but you're missing the point. If Facebook had prominently allowed pseudonyms in the first place it likely wouldn't have become as popular as it is today. It's the White Pages of the 21st century, and as I stated above, the White Pages would have been practically worthless had it allowed people to use pseudonyms.
You listed twitter as a "proof" that you have alternatives, as an example that FB is no monopoly.
I agree that Twitter is quite successful and big. In spite of allowing pseudonyms?
White pages don't apply. No idea how these work over there, but here they are a service to find a phone number - and sell a couple ads. You don't communicate via White Pages. In fact, you'd only use those to find people _that you usually don't communicate with_. And then _move the conversation to a different medium (phone)_.
Facebook is not related. It's not a simple register. It is not the same thing.
It's like comparing the hand-selected early Yahoo! link collection with the current Google, including Search, GMail, GTalk, G+.
