A one-way paper trail in favor of the company. If a boss tells me I'm fired for being "too black" and then deletes my slack (and I don't have a screenshot), I'm not going to have any leverage to get proof unless I can get a subpoena (which I wouldn't be able to, most likely)
I think you’re wrong. A subpoena would probably be granted for a situation where you know that the relevant evidence exists and exactly where it is. But it might not come to that in the scenario you describe, since the employer would also know that a third party has this incredibly damning evidence and would likely try to settle.
