This is "fake news" (I hate this term but it seems very relevant in this case).
As far as I understand Cambridge Analytica used the publicly-available Facebook APIs to create a stupid web app (a personality test or similar) which asked users to log in and hand over a lot of data (both about them and about their friends).
While their end-goal was against Facebook's ToS, I don't think there's anything they could've done about it ahead of time as 1) removing those APIs would hurt legitimate usage (let's say for example I am building an alternative client or similar - I want to be able to see my friends' data on there) and 2) it is still the user that is willingly giving out their and their friends' data when logging into such an app (and Facebook makes it clear what data the third-party service will be able to access when you first log in).
In short it's idiots logging in and delegating their permission level (which allows them to see their friends' data) to a malicious third-party. Facebook isn't really to blame there. It's no different from someone telling me a secret and then I go around and tell it to everyone else.
As far as I understand Cambridge Analytica used the publicly-available Facebook APIs to create a stupid web app (a personality test or similar) which asked users to log in and hand over a lot of data (both about them and about their friends).
While their end-goal was against Facebook's ToS, I don't think there's anything they could've done about it ahead of time as 1) removing those APIs would hurt legitimate usage (let's say for example I am building an alternative client or similar - I want to be able to see my friends' data on there) and 2) it is still the user that is willingly giving out their and their friends' data when logging into such an app (and Facebook makes it clear what data the third-party service will be able to access when you first log in).
In short it's idiots logging in and delegating their permission level (which allows them to see their friends' data) to a malicious third-party. Facebook isn't really to blame there. It's no different from someone telling me a secret and then I go around and tell it to everyone else.