Earlier quoted context omitted.
In 2020-2021 it seemed like 20-30% of my contacts were using signal as their SMS/MMS app of choice. Then they forced SMS users off the platform, giving some reasoning that SMS users don't understand which messages get encrypted, or something. I lost track of signal's usage and uninstalled it after it lost SMS support. At this point I don't know anyone still using Signal regularly anymore.
They removed SMS support because Google doesn't provide an RCS API, causing received RCS messages to fall on the floor. All carriers in the U.S. will default to RCS when messaging between Android phones these days.
That raises all sorts of interesting questions. Like how does some random person in some random part of the world using some random carrier know I'm using an Android phone today. Surely they don't.
Assuming they don't, how do they handle iOS not supporting RCS. iOS is over 50% of the phones in the USA. Dropping 50% of messages sent by Android phones is untenable. Whatever happens - that isn't it.
The next question is what happens if an RCS message arrives on a Android phone that doesn't have Google messages as it's registered SMS app. It would seem mightily unfriendly to just drop it on the floor if you have no one to pass it to. It seems far more likely it would just pop up in Google Messages.
But you can avoid all that if the sending carrier has some way of asking if the phone number they sending to supports receiving RCS or not. One way to do that is the RCS app registers with some central registry, and Google Messages only registers itself if it's the default messaging app, otherwise it doesn't. So you only get RCS messages if you are using Google Messages.
TL;DR: Google not publishing the RCS API is a red herring. It doesn't matter, just as Signal not publishing an API for sending messages using the Signal protocol doesn't matter.
If that is all true, then spokes people from Signal claiming RCS forces their hand was a best misleading. As it happens the other reasons they gave didn't look particularly convincing either. Which left me in the position of trusting them about as much as I trust Google. As Signal gave me no choice I now use Google Messages as my default SMS app. Everything is still seamlessly end-to-end encrypted if the other end supports RCS - in fact the feature sets of Messages and Signal are so similar it looks like they were copying from each other. But security wise it's a definite step backward from when Moxie was CEO.
Which brings to the final point - I can't see what any of this has to do with Moxie. It all happened when after he stepped down as CEO. Seems like this was some else's decision.