Yes, this is a conspiracy theory.
signal needs a phone number, GCM, and an age of 13; while discouraging anything but google-play and app-store builds and being hostile to forks. (Can silence even use signal's servers?)
You still have to trust signal doesn't leak metadata, and GP/AS builds being safe and private.
signal also just looks spooky, so I'm just gonna stick with XMPP/IRC.