(it won't help when the organization is beached, which unfortunately still seems to be the main way that user data gets leaked)
Ultimately, though, until there starts to be federal law mandating chain of custody for user data and harsh penalties on it being leaked, I think that this will continue for a long time...
Update: I should have read the article - did not realize TeleMessage was supposed to be E2E. I guess now the lesson is that you shouldn't be using normal devices for national security information (classified or not), and otherwise it's still not good to use a sketchy service that doesn't have Moxie-grade crypto implementations.