I don't think the discussion has shifted. It's just that the objection you're raising, that too much choice is a barrier to tool usage, doesn't really apply to this situation.
Given that this isn't overloading the user with a ton of options each time they launch an app, why is Facebook alarmed about users having the choice to opt out of tracking?
And I'll extend on that question: even if users are annoyed at a single extra popup that gets shown once when they install an app, why does Facebook care? Users will still pick the option that they prefer, they'll just be annoyed at Apple for asking. Why is Facebook alarmed that users on iPhone will have to spend a half second, once, saying, "ugh, Apple, of course I want a company to track everything I do online"?
Given that this isn't overloading the user with a ton of options each time they launch an app, why is Facebook alarmed about users having the choice to opt out of tracking?
And I'll extend on that question: even if users are annoyed at a single extra popup that gets shown once when they install an app, why does Facebook care? Users will still pick the option that they prefer, they'll just be annoyed at Apple for asking. Why is Facebook alarmed that users on iPhone will have to spend a half second, once, saying, "ugh, Apple, of course I want a company to track everything I do online"?