I suspect your address book is just names and phone numbers?
I use my address book for everything. I have my contacts' names, phone numbers, email addresses, addresses, IM usernames, birthdays, anniversaries, websites, workplace and other info stored in mine (not to mention some personal info jotted in the notes section).
Until today, I believed that information was secure. I had no idea an app could upload all of that information to their server WITHOUT MY KNOWLEDGE, much less consent.
Because of Google's approval process (or lack thereof), Android users have always been paranoid of the apps they install and what permissions they give them. As an iOS user, I never thought I had to worry about that because of Apple's approval process.
Does it make a little more sense why some of us are furious about this now?
Exactly. I was always under the (apparently totally mistaken) assumption that Apple's approval process was there to catch exactly this kind of behaviour. It's supposed one of the reasons why an Android-style permissions system is not necessary on iOS devices.
Recently it seems it's been coming to light that their curation process is not nearly as thorough as they would have us believe.
Are you sure all the people in your address book are as careless about that data? The friend with the restraining out against their ex? The minor celebrity with the unlisted phone number?
Are you happy with the possibility that a connection between you and someone else might be implied without being true? What if a known drug dealer* had your phone number in their address book? (Perhaps via a room mate or child using the landline to have called them once? Or through reuse of an expired disposable cellphone number?)
* or child pornographer, or political dissident, or terrorist, orβ¦