The chant, from Facebook and even some commenters on HN and elsewhere, was always "Facebook doesn't sell user data, that would be stupid. Facebook guards user data very well and uses it to target ads."

With this and previous revelations, we now know that those claims are completely false. The reasoning, as to why Facebook did it, doesn't matter. The fact is that they sold user data. Even if they gave it at no monetary cost, it was given to benefit the company, and hence the data was sold.

I suppose now we just have to wait for another report on how Facebook sold all its user data to data brokers around the world.