There's no mistake, from my point of view. Well, if it was a mistake, it will be to be discovered.
The Cambridge Analityca Scandal is just a proof of what had happened for years regarding the Facebook enterprise, though.  In my opinion, this is just the top of the iceberg, but, sadly, I don't think it is going to be a serious investigation. Just take a look at the Zuck's appearance in front of the Congress and the US Senate, look at the questions they made to him, as in a social reunion. It wasn't serious enough, it was just theatre.

The Cambridge Analytica scandal just put into the table something everybody already knew: Facebook surveillance and how the use of the platform can even change the way you think, But nobody cares, people still use the platform, still share anything they do and their relatives...