If you volunteer your data to Facebook I have a hard time considering you to have been “exploited.”
Further, I fail to see why "voluntering" it is relevant at all.
I've got no recourse against this - or maybe I have because Facebook is big enough that it's worth it to create targeted block lists. But against the next 20 smaller companies who do the same?
This is why there needs to be something else than just blindly trusting everyone out there. Because someone will not play fair if theres a competitive edge to gain.