Why would you have such conversations or expectations when using company chat? That's unprofessional and, frankly, stupid because it puts one's job in danger (as could an in person conversion heard by the wrong people at work). If you want to talk in private, there's dozens of other chat programs out there you can run on your own devices.
You really thought Slack somehow didn't have access to those messages or deleted them? That this feature wouldn't be inevitable? Their whole sales spiel is that they can keep all your messages forever. This shouldn't be surprising. I'm not missing the point at all. I always assumed they had an entire history and could reveal it at any time. It's not end to end encrypted. Assuming otherwise is dangerous and frankly, idiotic in today's world.
