INAL but will guess it is to make facebook GDPR-compliant. They show the data they have about us, but don't know if the apps that send the data to fb have used

INAL but will guess it is to make facebook GDPR-compliant. They show the data they have about us, but don't know if the apps that send the data to fb have used opt-in to enable sending data to fb. Maybe time to start writing emails to the companies who have uploaded our information without consent?