Richard Stallman's personal site.

https://stallman.org

For current political commentary, see the daily political notes.

The personal data that WhatsApp collects is also available to Facebook.
Use of whatsapp requires giving a phone number.
Using WhatsApp requires you to run non-free software either in the form of JavaScript code downloaded and run in the browser or through their app.
WhatsApp collects lots of personal information about each user, including data given to it by other businesses. Search in this link for "information we collect".
As for what they say about how they do or don't use the data, they probably do not interpret those words in the same way a non-lawyer would. Also, the FBI can demand all that data at any time without a warrant by means of the PAT RIOT Act, and it has no obligation to follow WhatsApp's policies at all.