People don't "upload things to a database", though, that's the point. They don't go to their photo app and think, "self, I'm going to upload this image to a global searchable database now". Rather, they think: "Steve and Mary would have liked this restaurant dish", or "I'm going to try and make my friends jealous of the great holiday I'm having".

Because people don't own their own clouds, or have privatized social networks, they are forced to upload things into databases that others control. Who controls the privacy defaults typically have the most control over where the data flows thereafter. And it's all out of the user's hands; they weren't given a choice, not a real one, because the incentives for the system lead you to accept the lack of control, or spend your life neurotically trying to keep a lid on everything, or live as a technological recluse. There's no other way to live today.