Facebook has a deep culture of pathological lying. They lied to the FTC [1]. They lied to WhatsApp and to the EU [2]. They created an Oversight Board and then lied to it [3].
Each of those lies are more substantial than lying in a privacy policy.
[1] https://www.ftc.gov/system/files/documents/cases/182_3109_fa...
[2] https://euobserver.com/digital/137953
[3] https://techcrunch.com/2021/09/21/the-oversight-board-wants-...
They can of course also have their app de-crypt and re-encrypt the messages to the key of a requesting third party like police or hired reviewers if certain keywords are used.
Authorities could also have Google or Apple ship a signed tampered Whatsapp binary to any user or group of users, like protestors, that uses a custom seeded random number generator so they can predict all encryption keys generated and no one else, including Meta, will know.
The variant of end to end encryption where third parties control the proprietary software on both ends, is called marketing.
As part of the Meta Companies, WhatsApp receives information from, and shares information (see here) with, the other Meta Companies. We may use the information we receive from them, and they may use the information we share with them, to help operate, provide, improve, understand, customize, support, and market our Services and their offerings, including the Meta Company Products. This includes:
- improving their services and your experiences using them, such as making suggestions for you (for example, of friends or group connections, or of interesting content), personalizing features and content, helping you complete purchases and transactions, and showing relevant offers and ads across the Meta Company Products
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Popular theory is they can't see or store your messages, but can analyze them on the client and profile you (e.g. interested in brazil nuts)
I can perfectly mean just the audio exchanges when both parties talk.
Also: E2E does not imply necessarily that they do not know the key.
We limit the information we share with Meta in important ways. For example, we will always protect your personal conversations with end-to-end encryption, so that neither WhatsApp nor Meta can see these private messages.