To be fair they’re not actually lying, they are misrepresenting the truth. Facebook actually doesn’t sell your data to third parties because they lease temporary access to it instead. Selling the data would mean they couldn’t recapitalize it with the same customers.

Meta’s customers couldn’t use it to skip doing their own market research and need to already know who they want to advertise to before they buy ads with Facebook. (It does provide insights and analytics about demographics during a campaign as well)