If it works like the Twitter integration it won’t be problem. You have to explicitly enter your name and password in the preferences. It won’t bug you, it won’t even be visible until you decide to take part. You have to care about it as much as you now care about the Chinese services Apple integrated.

Though I really do not understand your allergic reaction. Facebook seems like a tremendously useful tool to me since I always know that everyone is there. You don’t have to like it, you don’t have to use it – but you should at least be able to appreciate how valuable such an integration is to a great many people.