This is from 2016, but illustrates yet another way in which Facebook sold its data to be used to discriminate against its own users.

Facebook has blocked a U.K. insurance company’s plan to use information from customers’ posts in order to assign premiums.

Source: Facebook says insurance company can’t set premiums based on users’ posts.
We now know that Facebook’s data collection was used to discriminate against insurance buyers, home buyers, apartment and job seekers by de-selecting people based on their attributes. Hence, discrimination on the basis of health, wealth, race, sex and age is common on the Facebook ad network.