Two decades of it
Facebook has been aggressively violating user privacy (and even the privacy of people who don't use it!) for nearly 20 years now. And it's been lying for nearly as long about its privacy protections, how it deliberately turns off your privacy protections, how it buys up data from every online source you go near and all your financial info*, and what it does with that data. Every time Zuck or whassername gets called before Congress they spout new Big Lies about what they've done, why they've done it, and what they're going to be doing. And for that entire time the members of Congress have been slack jawed stupid suckers and nod and believe the lies they've been told. That seems to be fraying lately, though.
* For instance, even if you're reading this but not on Facebook, they know you exist, and they have a unique profile for you associated with your tax data, your employment history, all your credit card transactions, your bank transactions, your health history, your car insurance, where you live, what car you drive, who else is in your family, etc. etc. If they have any photos of you (say from the DVLA or DMV) then they are quietly tagging you in every photo a Facebook member uploads. If you have a forum history, they may have that. They do this for being a 'third party partner' that pays other companies to pass on all their data about everyone. If there's some entity who knows something about you, Facebook knows it. Often even an entity that wouldn't sell their data directly to Facebook (the DVLA might have a twinge about it) usually has other third parties they're using as consultants, and Facebook gets it from them. I hate Facebook, I've never used it, but they know more about me than my mum does.