Even if the specific act of letting the extension run is the fault of each user and presumably means they each violated Facebook's ToS, they can probably sue the extension makers for bribing the users to violate the ToS.
Each user only chooses to install the extension, the extension makers choose what data to scrape and I'm sure at least some of what's scraped truly belongs to Facebook, not their users or customers.
If a Facebook account can be considered a technological barrier protecting intellectual property, they could sue under DMCA anti-circumvention provisions. The users installing the extension could be accomplices but they're not really the ones scraping and collecting the data.
> If a Facebook account can be considered a technological barrier protecting intellectual property, they could sue under DMCA anti-circumvention provisions.
It would also likely make screen readers, screenshots, and many other things illegal. I don't think it can be considered a "technological barrier", but who knows what courts will decide.
That said, I'd be surprised if that's the angle Facebook is taking - because they did (and still do) the same thing with their phone apps collecting ("scraping") address book records and uploading them to facebook servers -- and that would be an estopple-able admission of guilt if they do (even if the courts decide against them in THIS particular case).
Each user only chooses to install the extension, the extension makers choose what data to scrape and I'm sure at least some of what's scraped truly belongs to Facebook, not their users or customers.
If a Facebook account can be considered a technological barrier protecting intellectual property, they could sue under DMCA anti-circumvention provisions. The users installing the extension could be accomplices but they're not really the ones scraping and collecting the data.