You mean WhatsApp wasn't doing this already? I'm surprised, considering how long it's been since Facebook acquired WhatsApp.
In any case, if you value your freedom (or at least your privacy), avoid anything Facebook-related to the extent possible. This includes www.facebook.com, www.instagram.com, WhatsApp, and webpages with a "like us on Facebook" button (unless you have a means of blocking said "like" buttons).
Also, if you value your friends' rights, don't let Facebook use you spy on them. That isn't a nice way to treat your friends.