Why don't people come forward with proof?

One thing that doesn't make sense to me is people saying that multiple companies like lockheed are in the possession of alien craft and potentially bodies. The narritive is that since these are not government entities, they can't be held responsible or forced to submit foia requests. That all makes sense but how does that same non government company also get to be protected from people telling us what exactly they have? They aren't a government entity so why can't whistleblowers just state ev...