Paraphrasing here, perhaps the best way to maintain a conspiracy, in the non-pejorative sense, may be to classify the evidence and run a systematic campaign of ridicule and misinformation so that whenever a whistleblower comes out they can be rapidly labeled as a look regardless of their bona fides.

I'm on the fence on this subject, finding both some merits and demerits to the arguments of both detractors and supporters of the NHI hypothesis. Until we have publicly available concrete data to analyze, all we are doing is speculating and slinging mud at each other.

The difference being that the proponents of the NHI hypothesis are all for obtaining and releasing such data, while the critics appear to be very comfortable with the status quo of secrecy.