Exactly. If it's 5 minutes per 1 billion customers, 5 billion minutes wasted. That's 9512 years. 135 lives.
That's close to the proportional death rate from air travel accidents (3.6 billion passengers/year, around 500 deaths).
Facebook takes---in Fermi numbers---about as many lives as plane crashes.
That's pretty much the kind of fallacy behind "if all people on Earth give 10$ for <cause> we can solve <big problem mankind hadn't solve in a century>."
135 out of 1B isn't big at all, it just looks big because of the biases we have when interpreting big numbers. Not mentioning the fact that the aggregation isn't very relevant (it's not like 135 people will have their entire life wasted while the others are not annoyed at all).
They're wasting 135 people's entire lives worth of time. Every single day. :(
Where are you getting that 1b number from? Most of Facebook's active users are presumably not receiving these emails or not being particularly enraged by them, since they like using Facebook.
Why the hyperbole?