If you only chat with private numbers, WhatsApp will operate exactly as it was before the privacy policy changes, Facebook will know nothing about you.
Is this correct?
In any case, that's assuming you talk with a business. So if you don't, will they sell that metadata too?
If you talk with a business, lets say a bakery, Facebook will know you talked with that bakery, and if you talk with a different business that other business may know it too. That's metadata about you that they explicitly say they collect.
But if you never talked with a business...what will Facebook know?
But if I don't interact...they can't (or rather they shouldn't). They state that you will never be contacted without you doing the first move, so even if all my closed contacts chat with the bakery Facebook will have 'this user is highly likely to contact this bakery' data, but can't do anything about that unless I personally contact myself, apparently.
Edit: nop, as their policy say: 'your contact list will never be shared with Facebook' so even if all my contacts chat with the bakery Facebook won't have the data 'this user is very likely to contact this bakery'.
Facebook can, of course, just 'ignore' their own policy and give this data to the bakery so that they contact me directly, but doing so will be a direct contact break. This is Facebook, it is not entirely impossible (unfortunately) but if they do it will be another scandal.
Is this the fear people have for WhatsApp?