Arguably, that was a curation and numbers issue. When it changes from 10s of letters a day to billions, curation becomes less of a concern and the argument can resurface.

Edit: for an additional example of this concern in the other direction - when a company or person or government tracks the movements of 10s of its citizens who are under active investigation, that's not seen as much of a problem. It's a numbers issue. When the same can track tens of thousands or hundreds of millions, suddenly it's a human rights issue around privacy.