For example, on WhatsApp, use the whole 25 character limit for profile name. Examples:
Bob Moved To Signal.org
Alice MovedTo Signal.org
CharlieMovedTo Signal.org
Say Signal.org, not Signal, because they won’t know it’s an app.
Use your about section too. Same on Discord, Steam, Instagram, etc.
Some people realized when Signal removed SMS support on Android that Signal is a private org that can make changes as they see fit, and there’s nothing you can do about it.
Other people get stuck on the fact that Signal requires a legitimate phone number in order to operate.
In both of these situations, the people up in arms usually don’t understand WHY the changes were privacy and security improvements and make Signal a better platform. But the argument about not being fully in control still stands.
So it could be argued that Signal may keep you safer than if you try to roll your own Matrix or SimpleX server, and it’s definitely a better platform for anyone who wouldn’t have a clue how to set up and secure their own server. But people have definitely had reasons for leaving it.
Personally, I use both Signal and Matrix, and push average people towards Signal.