They don't sell your data, the whole way they make money is by keeping hold of your data and selling targeted ads. Why would they sell away their competitive advantage?
Selling targeted ads is selling your data (not directly, but selling products that depend on your data). Are they going to continue to use your data to sell targeted ads to others?
Selling your data = "pay us $$$ and we'll give you the name, email, phone number, DoB, SSN, interests, credit score of a million users". Plenty of companies do this today (both legal and illegal), but Facebook isn't one of them.
Selling targeted ads = "pay us $$$ and we'll show your ads to people who match the criteria you select". This is very different from the former.
Anonymization is a myth. If you sell ads on proxy data, that data can be deanonymized. Also, Facebook may not directly sell your social security but they sure will buy it from the less scrupulous (but more honest) companies.
The ad space is data. If you chose the right categories you can reasonably identify someone. The whole purpose of behavioral advertising is to identify groups, you can make those groups =1 if your clever. Look up deanonymization. It's one of those problems that also affect researchers because it's hard to keep db data anonymous too.
You need to read up on how online advertising works. Or better yet spend a couple of dollars and try it yourself. None of what you are saying makes any sense.