I think he's talking about government backdoors, whereas a service like MegaChat could potentially offer true end-to-end chat.. However this doesn't seem to be

I think he's talking about government backdoors, whereas a service like MegaChat could potentially offer true end-to-end chat.. However this doesn't seem to be the case as A. you're unable to upload your own public key, and B it's still client-side JS. A subpoena would force them to pass on your session logs, encryption keys, etc.