Given what we have seen from Facebook so far I am not convinced they wouldn't sell data to anyone including Hitler as long as they paid for it somehow.

More realistically though I fully expect them to sell (misleading) data to insurance companies, Indian (and other) support scammers etc without asking many questions.

For that reason I prefer almost anything including email and Telegram.

(My opinions might be somewhat coloured by the fact that I was an enthusiastic Whatsapp user before Facebook bought them and even stayed and gave Facebook another chance with Whatsapp. )

If being known to be in contact with certain people (e.g. human rights activists) can be damaging to you, you need to use something other than whatsapp or to somehow make sure the phone number whatsapp knows cannot be connected to your identity.

Exactly the problem. My conversations should be utterly unexiting for anyone capable of getting hold if them.

I am personally more worried about FB selling (misleading) data to insurance companies. If their ad targeting is at the same level as everyone else they could get whatever conclusions they want from whatever data.

And then there is the issue about actual human rights activists and while I am not very active (monthly payment to amnesty) I don't want to support a system that scoops everyones data into the hands of "they trusted me" Zuckerberg.

Even worse I was with Whatsapp and gave Facebook another chance until it was clear that datamining everyone was the only reason they bought the company.