What they sell is the ability to target you based on it. But the data never leaves FBs servers!
So if you remove the tags from your settings, advertisers won’t be able to target you with them anymore
You could argue this is the user’s own fault, but prior to Cambridge Analytica, there was very little public understanding of what “connecting” an app to Facebook really meant among the general population.
Also, just because Facebook doesn’t sell this data today does not mean they never will.
But Facebook issnt selling that access! Access to the APIs is free.
Now users just giving any random app access is a whole different can of worms...you have the same issue on Android and iOS with permission dialogs...people worry about Amazon Alexa recording everything they say, but will give any app microphone/camera access to do just the same if the app creator is ill intended.