Signal has been used widely in US intelligence for many, many years. Nothing about this is new, though perhaps people that never paid attention are just now becoming aware of it. As for the rest of Five Eyes, they use WhatsApp the same way. I’m not sure that WhatsApp would be considered an improvement.
It is clear there is a gap between how people imagine this works, or should work in theory, and how it actually works.
This is a factually incorrect and very naive take. The same topic has been in the news in European countries too about the widespread use of WhatsApp when discussing secret information. It isn’t just the US government, everyone is doing it.
They're paying attention to Signal now because Hegseth doesn't know his ass from his elbow when it comes to tech and secrecy, instead acting like someone who has watched too many action films and thinks those are just like real life. The problem is not Signal. The problem is incompetence. Plain and simple. Because he blindly added persons to the group that probably didn't belong there, we now have the infamous "we have OPSEC" line, but instead of questioning why this idiot still has a job anywhere near the intelligence agencies, we're wasting our breath scrutinizing what is easily one of the best opens for secure comes if the user understands how it works.
It is clear there is a gap between how people imagine this works, or should work in theory, and how it actually works.