Yes because the US does not want you useing a central server in its jurisdiction so it can force the organistation to give out all the meta data while not being alowed to alert anyone. How dare you use something that could give the US so much information in one easy package
Did I say the prefrence was to use normal telecomunication providers? or that the internet in general where super secure, no, but Signal is not secure either, and it in all likelyhood a honey pot