First that's like saying a bar that gives away drinks with every bag of peanuts isn't selling alcohol. The fact that ad was only shown to a specific demographic reveals that the person clicking it is in that demographic.

But second, sure they didn't sell it, they gave it away. Facebook claims the data delivered to Cambridge Analytica wasn't sold. No, it was given away because facebook calculates that it benefits from research which improves targeting on their platform. Nobody is fooled by any of this, unless they choose to be.

> reveals that the person clicking it is in that demographic.

But you don't know who that person is [ until they create an account or give you info ]