I know in general there's the whole "the company pays for it, the company owns it, the company can audit it" corportesse oblige, enshrined in case-law yada yada, but one of the things I always liked about Slack was it seemed to have a bit of that old counter-culture sneer around "yeah, that may be true, but we code for the user anyway". This is very much an anti-user, pro-corporate maneuver, and I think it's a shock to many who took Slack's long-time messaging to the contrary at face-value.