So NLRB handles confidential complaints. The complainant's idenity might be kept confidential. Exact details may be kept confidential.

Why aren't we to believe that this is Elon Musk going after anyone filing a complaint to the NLRB (from X, Twitter or SpaceX) or, worse yet (from Elon's POV), anyone potentially organizing any unionization effort?

There's absolutely no reason DOGE should have access to this information. There's absolutely no reason their activity, such as what information they accessed, should be hidden.