The problem today is that some (many?) politicians either don't understand or agree with those goals and pick more convenient tools that they may have been used to as a civilian.
There was nothing necessary about the conversation that couldn't wait for a secure location. The government will go as far to set up a secure comms room in employees homes if needed, it's not like they don't know how to secure communication.
A lot of us have had to work within specific constraints for data security, I've had to make hour long trips because I forgot a secure laptop in my office. No one would have died if I did some work on my personal device, but I still went out of my way to follow procedure.
These people have the self control of toddlers.
There are more than enough enterprise chats out there with security levels ranging from "good enough if you trust a major US corp" (Teams DoD) to "complete paranoia" (finance communication apps with on-premise encryption/decryption modules plugged into your HSM)
End of day, you just need to communicate, most software, how ever outdated, should be sufficient.
It’s a user problem, blaming software is a distraction.
When you design a feature for a business app, it has to be immculate, brain dead easy to use, and be explained 9 times in 3 different training seminars before anyone will figure it out.
Meanwhile, if the new hit filter on TikTok was buried under a hidden search, with a feature toggle, consent form and rotating secret password, end users would figure it out in 5 minutes.
As you say, people are spoiled.