"why are you surprised that people are surprised?"
It'd be surprising if there wasn't a clear or direct causal path about how Google found that information. For example, imagine that you paid for a hotel room somewhere in Thailand by cash, didn't carry your phone with you at the time, didn't log in to any electronic device, and still Google inferred that you stayed there, THAT would be surprising.
On the other hand, literally parsing out an email (AND even linking to it, you can click on the notifs to take you to the relevant email!!!) and showing you the result doesn't in any sense qualify as surprising.
It wouldn't be "surprising" if the mail parsing were done 100% client side, with a 100% certainty that no data is gonna be sent back to the mothership. But since it's done 100% server side I cannot honestly know what they are going to do with that data and knowledge.
It'd be surprising if there wasn't a clear or direct causal path about how Google found that information. For example, imagine that you paid for a hotel room somewhere in Thailand by cash, didn't carry your phone with you at the time, didn't log in to any electronic device, and still Google inferred that you stayed there, THAT would be surprising.
On the other hand, literally parsing out an email (AND even linking to it, you can click on the notifs to take you to the relevant email!!!) and showing you the result doesn't in any sense qualify as surprising.