Moxie exists because he helps centralize metadata collection on users looking for e2e encryption. All CIA has to do is pop the server when a fresh zero day vuln is found and collect. Signal protocol can be "secure" and still a useful asset to intellegence.
Even its E2EE scheme is an oddball non-audited homemade one instead of an audited standard one like in Matrix for example. Telegram is fine as a Twitter alternative but I sure as hell would never rely on it for secure messaging.