Actually, I don't believe they can keep the information to themselves, even if they wanted to, as they are based in the US. So it seems like my facebook account will not be long lived if they start asking me these kind of questions. Not only are they gathering too much information, with this they also pass a moral line. Since you are asked to provide info you have and naturally, the top 2 answers in the poll will be "yes" and "no". "I don't want to answer" will be the last item in the list. As a result, people will mostly answer the top 2 answers.
I agree that they can't. Their business model is to aggregate identities and monetize them to various market segments one of which is the US government. I don't believe there is anything facebook wouldn't try to stick in a database and sell.Actually, I don't believe they can keep the information to themselves, even if they wanted to, as they are based in the US.