As far as Facebook has explicitly stated, the reason for the "changes" to their terms and conditions was to be able to launch a feature where businesses with a Facebook page could use what amounts to a "hosted client" in order to do things like customer service or have chat bots and the such, all with multi-level permissions as you see with other platforms. This feature has been "a long time coming" (in that they have been talking about it publicly on their site for I think two years).
You could argue that anyone could already technically (though against the terms of service) build such a service, so "end to end" only applies to a user's selection of their "end", but since Facebook is WhatsApp, a statement that Facebook never has access to X or Y or Z is no longer true, and so they carefully went through everything and adjusted those terms in a way that was confusing, totally forgetting that this is the Internet and no one would understand the nuance.
The original big article about this had a statement from a Facebook representative about this that went out of its way to note that nothing was going to change for "non-business chats and account data", but almost no one seems to have even paid attention to what was actually going on or what was changing. I am betting that Facebook saying they are delaying this rollout now is going to include them spending more time on the wording to make it clearer (not that I bet the people who like to get upset about this stuff will read it carefully).
> The move, the spokeswoman said, is part of a previously disclosed move to allow businesses to store and manage WhatsApp chats using Facebook's infrastructure. Users won't have to use WhatsApp to interact with the businesses and have the option of blocking the businesses. She said there will be no change in how WhatsApp shares provides data with Facebook for non-business chats and account data.
Then, a couple days later, people were going crazy over an update to their security whitepaper that now supposedly claimed that Facebook no longer didn't not (double negative, sorry) have access to a chat's private keys... but the update was actually careful and rather specific to scope it correctly to this new hosted client for businesses feature, having the following paragraph, which seems to still be sufficient and carry the same goal as the removed sentence elsewhere.
> All chats use the same Signal protocol outlined in this whitepaper, regardless of their end-to-end encryption status. The WhatsApp server has no access to the client’s private keys, though if a business user delegates operation of their Business API client to a vendor, that vendor will have access to their private keys - including if that vendor is Facebook.
As far as I can tell, this change was blown entirely out of proportion into what almost feels like a hit on one of the few secure messenger options we have, and the only one that actually "works well" for all users, including true "end" users who barely understand what they are doing. Hell: WhatsApp is an interesting case of a product that was less secure before Facebook bought it and meddled, as it wasn't originally end-to-end encrypted!
Now, I do appreciate the arguments from people who say "you can't trust the WhatsApp client, as it isn't open source". As a reverse engineer, I think people have a bit of a warped perspective of the value of this, as I can both easily show you how to hide a backdoor in an open source project that no one will question you on (just throw in a use after free bug with an info leak in your network stack) and also attest to how "easy" (for someone like me) it is to audit these things to at least surface verify it isn't doing something ridiculous in the general case (for all users, not for you in specific... but again: that is also true of the open source client!).
That said, I really really do appreciate the point: this kind of software should be open source with secure reproducible builds, and it should have open protocols and alternative clients (which FWIW, Moxie doesn't believe in--he won't even allow Signal in F-Droid--but that's another argument). If someone wants to never use a program for this that isn't open source, I totally can buy into that belief system (though I am also going to hope they don't use an off-the-shelf closed source operating system, for some consistency).
But... none of that changed two weeks ago. If you were happy with WhatsApp before two weeks ago, it seems like you should still be happy now. And if you weren't happy with WhatsApp before two weeks ago, I can't imagine you will ever be happy with WhatsApp. You, FWIW, sound like you might have been in the first category of people, not the second? You also just seem to despite Facebook to the point where it doesn't matter what they do, good or bad :(. Regardless, to the extent to which a subset of the second people tried to capitalize on uncertainty here to essentially misrepresent what was going on as a massive change, I want to say "shame on them", as that feels like dirty politics to me.