Or why did hundreds of thousands of users actively choose to share their data with a random company called Cambridge Analytica?
They certainly have never chosen to do so. You can accuse them of participating in some innane quiz, but it was exactly the big scandal that not only the participants' data, but also that of their friends was sucked and resold to Cambridge Analytica without their knowledge by the "researchers".
All participants have actively clicked a button to confirm that they would give Cambridge Analytica access to their profile data and data from their friends.
The scandal was not that the data was collected without the participants knowledge. The scandal was that they used the data for something else, than what they initially had told the participants.
They certainly have never chosen to do so. You can accuse them of participating in some innane quiz, but it was exactly the big scandal that not only the participants' data, but also that of their friends was sucked and resold to Cambridge Analytica without their knowledge by the "researchers".