Well there are alternatives to signal. Some use p2p, some use tor, some use a federated system of servers. None have the networking effect to be as secure and as popular as signal.

So if signal was privacy preserving, didn't show or tell contacts about others using the service, do you think it would be as popular? Or do you think we'd be discussing a different popular e2e encrypted app and complaining about the very features that made it popular?