One thing that TFS doesn't make clear here is that this situation only occurs if you sign up for Pokemon Go with a Google account.
The game supports two different account types, either a Pokemon Trainer Club account through pokemon.com, or a Google account. Because the game is incredibly, absurdly popular right now, Nintendo is throttling Pokemon Trainer Club account creation to prevent their servers from becoming molten silicon. Which is why so many people are signing up with their Google account.
It's signing up via a Google account that causes PoGo/Nintendo to have full access to said account. Which means that if you have already signed up via the Pokemon Trainer Club, or will do so in the future, you'll be fine. It's only users signing up via the Google account system that are getting their Google accounts linked in this fashion. So the straightforward solution is to only sign up for the game with a Pokemon Trainer Club account. Which admittedly isn't super helpful due to the aforementioned throttle on Pokemon Trainer Club account creation, but there is at least a workaround.
Otherwise the iOS-centric aspect of this is a bit unusual. Obviously iOS isn't giving PoGo access to your Google account, rather it seems to be a difference in how the two apps work. It appears that the Android version of the app doesn't try to request full permissions, only the iOS version does. Why? That's a good question...