You don't call up Facebook and ask for a few TB of data. You use ad targeting services which are essentially an abstraction on top of a personal data aggregation and analysis system.
That's just obtuse. It’s clearly not selling user data at all. When I buy FB ads I cannot not get any user data. I can pick they type of user I want to see my advert, but I cannot know who they are.
If you have a FB account you can try this and see for yourself right now for a few bucks.
But maybe I'm wrong. Can tell me how they do sell user data?
I might gave this wrong, but only the users saw their own data in the ads they were served. Signal can choose lots of parameters for who should see their ads, but they dont get to see who those people are.
In this case, they plan to transfer user data into another division of their company. They have bought WhatsApp LLC, with cash and shares in hand, and got (among other things) user data in return. This is a pretty clear case of selling user data of such a company, isn't it? (Note that GP never claimed that Facebook itself sold any data just that they exploit data commercially - they have given third parties extensive access to user data in the past though)
Anyway, these discussions on the technicality of the term "selling data" vs "selling access to users using data" is just means to deflect from the real problem. It doesn't get away by rephrasing.