I think the point here is that Play Store and the App Store have no requirements for public source code accountability so there is simply no way to know if a gi

I think the point here is that Play Store and the App Store have no requirements for public source code accountability so there is simply no way to know if a given app binary is safe or not. Even an open source app on these stores can't be provably correlated to published source code and could have undocumented deviations at any time. Put simply, there is no reasonably accountable privacy story on stock iOS or Android. You mostly just have to take each publishers biased word for it and that the permissions systems alone covers every potential way an app can abuse your trust.