Earlier quoted context omitted.
The problem is that the world you're arguing for is one where I get all my friends to sign a contract before I give them my personal details. Nobody wants that, not even in exchange for whatever Facebook provides. It's a perverse expectation rooted in some kind of idea that all human exchange must be regulated by some contract. And thieves are indeed liable for returning money.
But what's the real answer? Imagine my friend writes down my phone number in his iPhone's contacts list, and then installs an app – let's say some random game. The game asks for permission to access contact info, which my friend grants because he's careless. The game steals contact info and does various nefarious things with it. In this analogy, Facebook is Apple, and Cambridge Analytica's app is the phone game. I do…
It doesn't stop your friends from oversharing but it creates a contract between you and the party requesting your information so there's now some legal recourse for how they use your data. And if the law creates liability for app distributors to ensure apps follow the law then Google and Apple are now on the hook for allowing violations.