Nothing is stopping anyone from running their own servers, changing the username scheme, and implementing the voice signaling. Moxie doesn't complain about such usage. But that's more work than simply complaining and telling OWS what they should do.
As far as usernames go, that would require the signaling key to be remembered by the user. That doesn't work well in practice. As far as contact sync goes, has anyone submitted a patch for the android client to add an advanced option to disable that? On IOS access to the address book is user controlled at runtime. destinations will be validated by the server at compose time. Regarding federation, let's see some code. It's ridiculous to demand the small team that is OWS solve every single problem.
As far as usernames go, that would require the signaling key to be remembered by the user. That doesn't work well in practice. As far as contact sync goes, has anyone submitted a patch for the android client to add an advanced option to disable that? On IOS access to the address book is user controlled at runtime. destinations will be validated by the server at compose time. Regarding federation, let's see some code. It's ridiculous to demand the small team that is OWS solve every single problem.