As I said above, most corporations advise employees to raise legal concerns to lawyers. This makes those concerns privileged and ensures the concerns go to people who can, you know, professionally evaluate them.

So I don't think you can reasonably say this is a case of companies not wanting illegality to be disclosed. It's wanting disclosure to take the proper form.

(Indeed, they have a vested interest in proper handling of illegality to ensure that higher-ups are aware of and can mitigate legal risks.)