If you want to rip in to Apple or Google or Uber for claiming they should have a pass for using privacy tech, feel free. Understand that this is distinct from most research on differential privacy.

The US Census collects demographic data about as much of the population as they can manage, and releases summary data in a large part to support enforcement of the Civil Rights Act. They have a privacy mandate, but also the obligation to provide information in support of the rights of subpopulations (e.g. Equal Protection). So what's your answer here? A large fraction of the population gets disenfranchised if you go with "avoid sharing the datasets".

You end up with similar issues in preventative medicine, epidemiology, public health, where there is a real social benefit to analyzing data, and where withholding data has a cost that hasn't shown up yet in your analysis. Understanding the trade-off is important, and one can come to different conclusions when the subjects are civil rights versus cell phone statistics. But you are wrong to be upset that math allows the trade-off to exist.