Whatsapp does not upload and store the entire content of your address book. It only sends phone numbers to check whether they can be reached via Whatsapp (and of course you can prevent even that by not giving it permission to access your contacts). They also have a much clearer privacy policy.
https://www.whatsapp.com/faq/en/general/20971813
"WhatsApp looks at the phone numbers in your address book and then checks to see which of those numbers are verified in WhatsApp. This allows any WhatsApp users from your address book to appear as contacts in your Favorites list (Contacts tab on Android) and the Chats screen.
During this entire process, only phone numbers are sent to WhatsApp for lookup"
[doublepost=1463604744][/doublepost]Not to mention home and work addresses, employers, job titles, birthdays, email addresses ...