This happened to my girlfriend and me twice on Messenger. On two consecutive nights, we heard a male voice with an American accent speaking as if he were talking to someone else, almost like they were conducting some kind of operation. It seemed as though he suddenly realized that we could hear him, after which the voice abruptly disappeared. The following night, it happened again, but this time the voice sounded like that of an African American woman. The situation was similar to the previous night. From that night, we have not used it to communicate and used Signal instead.

one thing to consider is how just the optics of major players using e2e was an overall benefit.

people who otherwise would have gone their entire lives without ever hearing about encryption were exposed to the term and the marketing convinced them that encryption and privacy was a valuable thing, even if they didnt fully understand the mechanisms or why e2e might not necessarily be very effective in specific circumstances.

later, when presented between option a and option b, where one has encryption and the other doesnt, they are more likely to choose the one with it ("well, if instagram and facebook use it and say it is good...")

I don't disagree, but I think there is a distinction between "everything is e2ee, but specific conversations may be MiTM without detection" and "nothing is e2ee and can be retrospectively inspected at will" that goes a little beyond security theatre - makes it more analogous to old fashioned wiretaps in my mind.

Obviously it involves trust that it isn't actually "we say it's e2ee but actually we also MiTM every conversation"

One of the scary things is that not even this really works. Ignoring supply chain attacks, most people treat any client as effectively black box. When was the last time you read through the code of a messaging app? How do you know its safe? Maybe _you_ read through it, but 99% of people don't.

It's all about trust at the end of the day. And given that it was exposed that Apple, Microsoft, Meta, Google etc all collaborated with the US government to provide surveillance (PRISM) by Edward Snowden, how we can trust them ever again?

E2E encryption lets Meta turn down government subpoenas because they can say they truly don't have access to the unencrypted data.

I can't say I really mind this change by Meta that much overall though. Anyone who's serious about privacy probably knew better than to pick "Instagram chat" as their secure channel. And on the other hand having the chats available helps protect minors.