> But unless that merchant is very specific, the card company doesn't know what I've bought.

But the merchant knows and (unless it's a very old mom & pop shop), they didn't do it manually, the itemized receipt is in their computer system. Which the government can easily obtain and correlate with the credit card transaction so now they have both.

As the downstream comments say, if you're any kind of persecuted minority, this is a big problem.