Re: How is Apple supposed to prevent use of email addresses to identify people?
If you read the article this has nothing to do with voluntary user supplied data like an email address. It is to do with device fingerprinting and tracking using hidden identifiers without user consent.
If you want to have a problem with the article or research go for the classification of Crashlytics as a tracking library. Obviously I haven't read the code so it might be doing some behind the scenes tracking for Google but for the app dev it is reporting on crashes and errors and is not a tracking or advertising library. I doubt the usefulness of a tracking library that only tracks users for whom your app is crashing.
Similarly Firebase Analytics is not necessarily a tracking library but it can be used for that depending on how you implement it. Merely detecting the existance of one of these libraries and declaring the app tracks its users is poor science imo.
Biting the hand that feeds IT
