[pfranz]

If that was the case I imagine you could ding Apple on false claims. They pretty prominently claim "Differential Privacy" both in their keynotes and on their website. Their claims are also that data is anonymized before they process it. Other companies have been a lot more vague and hand-wavy about "anonymized" in my experience and you're absolutely right that a lot of anonymized datasets can be de-anonymized by correlation.

https://www.apple.com/privacy/approach-to-privacy/