There are ways for them to do this securely, and nothing Musk has said has implied they won't.
However, if it is not open-source, we will always have to just take their word for it. Not only that they aren't being malicious, but also that they don't have accidental vulnerabilities.
Facebook has a end-to-end encrypted messages feature and, if you trust that they did what they say they do, it is secure. Like I said, though, since it's not open-source, you never know if you can trust them. But they did work with the Signal foundation to develop it, so that's at least a plus.
And, another plus, is that you can use it to send things that Facebook Messenger normally blocks. For example, the link to patriots.win. You can't send that on regular Messenger, but if you switch to their encrypted messenger, you can. This is because encrypted messages can't be moderated like this, because Facebook has no idea what is in it. Obviously, they could just remove the blocks in order to perpetuate the illusion.
There are ways for them to do this securely, and nothing Musk has said has implied they won't.
However, if it is not open-source, we will always have to just take their word for it. Not only that they aren't being malicious, but also that they don't have accidental vulnerabilities.
Facebook has a end-to-end encrypted messages feature and, if you trust that they did what they say they do, it is secure. Like I said, though, since it's not open-source, you never know if you can trust them. But they did work with the Signal foundation to develop it, so that's at least a plus.
And, another plus, is that you can use it to send things that Facebook Messenger normally blocks. For example, the link to patriots.win. You can't send that on regular Messenger, but if you switch to their encrypted messenger, you can. This is because encrypted messages can't be moderated like this, because Facebook has no idea what is in it. Obviously, they could just remove the blocks in order to perpetuate the illusion.