I’m just stating my opinion. What you linked to is only part of the story however
They collect a database of all your contacts including your personal phone number and they’re storing it all on a proprietary server. The LibreSignal project wasn’t created just to bring websocket support back before it was officially implemented; it also made efforts to remove unnecessary analytics like giving the LibreSignal servers access to your contacts list. Moxi didn’t like this at all, and from what I saw on the github discussion he was worried about losing server-side control of Signal development.
My original point is that there are better, more secure ways to message friends that just require a little know-how to setup if you’re determined.