By definition the channels that they are blocking are public. They offer end to end encryption, which should be as secure as reasonably possible in any communi

By definition the channels that they are blocking are public. They offer end to end encryption, which should be as secure as reasonably possible in any communication medium. Hopefully they will make their server code public soon so it can be reviewed. There are promises to do so, but they want to implement a federation protocol before doing so.