> You are saying that differentially private census data couldn't be used for gerrymeandering and advertisement while non differentially private data could?

They definitely didn't say that. You said that. And you said that because you would prefer to argue impossibility vs. possibility rather than more useful vs. less useful. You prefer this because for the first irrelevant question which no one asked (it is possible to use current census data in bad ways), you are obviously right; and for the second, relevant question (would allowing this data make it easier and far more useful for gerrymandering and advertisement), you are obviously wrong.

> for the second, relevant question (would allowing this data make it easier and far more useful for gerrymandering and advertisement), you are obviously wrong.

Really? Why? When has gerrymandering ever relied on identifying individuals? Have any advertisers ever tried to use census data to identify individuals? That strikes me as highly unlikely - they are gonna use Facebook and Google, not some government database they’d have to deanonymise.