The fact that giant companies keep your data and don't delete it when you tell them to has been true since the beginning of social media. Your things are not deleted, they're simply marked as deleted so you don't see them. The actual binary data never goes anywhere.

The rule of thumb is that if the data leaves your possession then assume someone has a copy of it. If it is encrypted and you don't control your keys then it isn't encrypted. (See: Bitlocker keys and Microsoft)