So, now we can't use Teams to have the "water-cooler" moments that supervisors claim we need, but really we are having them on Signal or IOS and they just can't measure that. Organizations really, really, really hate transparency.
Remember the famous "will the atom bomb test ignite the atmosphere" gentleman's bet those scientists had? Nobody actually thought it would but they discussed it semi-seriously. Today discussing some fanciful bad outcome like that (be it the mundane failure to deliver a product or something more interesting) is a liability when it's sitting in your company email servers. Even if that bad thing isn't what winds up happening or the people speculating aren't in a position to have accurate info the other side's lawyer or the regulator will try and construe it as proof that the company should have known ahead of time.
Or, more likely, say there's some sexual harassment or adultery kerfuffle between employees. It's way better for the company if none of that happened on company provided communications tools.
From the company's perspective it's avoidable risk to have work communication tools be used for informal BSing between employees. But they can't realistically prevent that so they introduce Skynet in order to make people watch their mouths and move those sensitive conversations elsewhere.
That's entirely intentional. You really don't want internal evidence of something that's going to be construed 10 years down the line as cancel-worthy, or worse, something that politicians/regulators are going to take out of context to attack you with.
I don't know what I found funnier, the idea that some poor fool at a Soviet embassy had to listen to our conversation because a key word hit caused the recording to be saved, or the idea that the author even proposed that the idea would work.